need some help for compatibility and dual channel ram

[BlackPercher]

my pc has the motherboard asrock b450m pro4-f
i am currently using only 1 8gb ddr4 2666 mhz crucial CT8G4DFS8266.M8FJ CL 19 1.2v

the thing is i bought at the start only 1 stick cuz i was going to get another stick later on for dual channel, now the only sticks i can find in my country are CB8GU2666 and CT8G4DFRA266 both are ddr4 crucial 2666mhz and i believe cl19 1.2v 
which i tried looking on the motherboard compatibility page and couldnt find them so i dont know if they are compatible with the motherboard and if i buy one of those if it will work with dual channel

https://www.asrock.com/mb/AMD/B450M Pro4-F/#MemoryMS the page for the motherboard compatibility list

[Chris Pratt]

What CPU do you have, because honestly, 2666MHz is no good for virtually anything you'd be slotting into AM4, anyways, especially at CL19. That is just atrocious. You should really try to get at least a kit of 3200MHz CL16, or better, 3600MHz CL16. Otherwise, you're just going from horrendous performance to slightly less horrendous performance.

[BlackPercher]

ryzen 5 3400g i believe max supported speed is 2933 mhz
also the main reason, budget, even now only have budget to buy 1 stick of ram
btw i remember not seeing a lot of diff beetween 2666 and 3000 mhz, like 4-10% on benchmark videos, but without dual channel there is a lot more difference, still only had budget for 1 stick at that moment, then corona happened lost my job bla bla bla, now i can afford the another stick i was planning when i bought the pc the problem is i dont find same model on mercadolibre colombia, dont know if trying another brand would work, and if so i still need to check if my motherboard is compatible dont know what to look for etc