OP’s objective is apparently to deter Samsung users from switching away. Your experience, however, is too special that even people in this Samsung sub are not convinced.
I upgraded from SE2020 for the 5G connectivity. Afterwards I have been enjoying features like Magsafe / better camera which I did not care about. If you are still happy with the phone, just stay with it, but pretty sure you will have another level of satisfaction by the upgrade.
Sometimes when I do a lot of multi-tasking, the app is killed by iOS. A possible flaw could be from the app itself, but the logic behind airplay also plays a key part.