Any phones that don't turn off other SIM when receiving a call on a different one

[venomtail]

Dual SIM is a nice feature to have on phones and I wish companies would go further with letting us get 3 SIM phones (at least let eSIM be a 3rd SIM option) so I can 3 number on a phone active at any given time, however there's one gripe with this.

 

Whenever I receive a call on one SIM, the other one shuts down. I won't receive calls on the other one (I'm not even informed I'm missing a call since you know, it's not working since I'm on one live), the internet is disabled so any hotspot devices shut down whilst I'm receiving a calls and just rough edges what feels like. Ideally everyone should move to WhatsApp, Signal, Messenger and Discord calling but can't shift an entire industry.

 

Two questions.

1. Why is this a limitation? Just let me keep the damn internet on whilst receiving calls on the other one and inform me that I'm missing calls whilst being on a call.
2. What phones exist out there that don't have this issue? Not a bleeding problem and not yet upgrading out of necessity but something I'll have to consider for the future. For reference, I'm using the S23+ that has this problem. Should I have gone Ultra or would it be the same?