NeverNotExhausted

If your motherboard is smart enough, it will downclock to a speed that both sets of memory are capable of running. If not, you'll have to find that limit yourself, but it's not a hard thing to do. Sometimes even identical sets of memory don't play well together, so don't expect anything to work without testing

IQRL_more or less usually is caused by memory. I've come across this on a lot of old Thinkpads, the usual fix for it in the thinkpads is to take the RAM out of the system and give the contacts and the slots a good clean with compressed air/a good blower, and to give the contacts on the RAM a quick touch up with IPA. Sometimes a laptop just doesn't like running dual channel memory, so try boot it up with a single DIMM in and see if that helps with reliability.

What's your workload? Are you only gaming? Or are you running multithreaded tasks? If you're only gaming then the 7600x will be a noticeable improvement due to improved IPC and increased clocks. If you're hitting multiple cores, then you might even see improvements staying on AM4 and getting a 5700x or one of the higher core count models on that platform. Of course these improvements will be even greater if you went more cores and AM5

Whenever I stream a game that isn't available on Steam I typically use AMD Link, On my last system I was using Nvidia Gamestream and both work quite well. I also quite regularly use Windows' built in Remote Access tool quite a lot when I need to leverage my main desktops power from elsewhere in the house, but that's only applicable to streaming to another Windows device and it's a bit more laggy than the other options.

That should work fine, I run a similar setup for gaming in bed on my phone. My desktop is wired into my home network and then I have a wireless access point in my bedroom that only gets used for my laptop and phone for streaming steam games and it works really well. Just make sure you're close to your wireless access point while streaming, you'll notice that the image gets noticeably worse as you get further away from it. Your ISP won't have any effect on streaming within your own network either, the limiting factors will be the hardware within your own network.

Double check if the M.2 will only work with a WiFi/Bluetooth module, or if it will work with an M.2 sata controller/adaptor. If it does then that's the route I would be taking. I've never used one myself so I'm not sure how well they would work if you intend on running RAID, but they're relatively inexpensive and it's a fun project to have a go at. The tricky part would be powering them, you could try find a small mosfet board, jack 12v directly from the laptops PSU and signal from the laptops mobo so the drives start up when the laptop does? That would be a pretty fiddly solution though, and you'd have to step the voltage down from 12v to 5v so you don't fry your drives. The easy route in my mind would be to get a powered USB hub and run the 3 drives that way. Being a powered hub you wouldn't have to worry about staggering the startup all that much.

Eh, if you have a decent enough wireless access point and phone then you shouldn't have issues to begin with. You'll find a lot more benefit out of having your PC wired instead of using WiFi on the host end, it's also cheaper and easier in most cases to go about it that way than it is to create a dedicated wireless network just for streaming steam games. EDIT- In saying this, I have set up a wireless access point closer to where I stream games to my phone for similar reasons to yourself.

Samsung have been the go-to suggestion for years because they develop everything in house (NAND, Controller, Firmware etc). Most drives from reputable brands are still very unlikely to have issues though. I have drives from Samsung, Team T-Create, PNY, Crucial, Patriot, and Kingston in various systems in my home and never have had reliability issues. I just buy whatever is the best deal for the application and performance spec that I need regardless of brand.

@Levent Got a good chuckle out of your signature

Varies from motherboard to motherboard. Usually it will be somewhere near the CPU settings in the advanced view of your BIOS. Tons of useful Youtube videos around to see what to look for like the one @Leventhas linked up above. Each motherboard vendor might have it tucked away somewhere different in the BIOS, but they all end up doing the same thing. A good rule of thumb is that the default memory timings will be stable *Most* of the time, especially if you run clocks at lower speeds than the RAM is rated for. For context the memory in my main rig at home is rated for 18-22-22-42 timings and 3600Mhz. But I can only run it at 18-22-22-42 3400Mhz because the memory controller on my CPU can't handle 3600Mhz. From what I can find online on your memory, the timings are rated at 16-18-18, so leave that alone. But manually set it to 2400Mhz, run a Memtest, then bump it up in increments of 100Mhz or so and run another test until you find the point where the system isn't stable anymore. Then set it back to the highest frequency that it was stable for.

If a system wont boot because of memory incompatibility then it will usually default to a known compatible profile. You won't be able to push past 2400Mhz using XMP, you'll have to do it manually if you want to try higher clocks

Seems like pretty normal Steam behavior. Steam's client is Chromium based, so it would make sense for it to mess with Chrome while it does it's thing