I used to have to re-establish my internet connection on my most-used Roku (3810 listed in my sig below) several times a month. (The others, a 3600 on a seldom used set in the guest bedroom, and the Roku TV in the bedroom mainly used by my wife viewing DirecTV kept connections very well.) It's been several months now since I replaced an old Western Digital router with a new ASUS TR-AX3000 and I haven't had to re-connect the 3810 since.
I suspect my Roku 3810 does not recover from wifi instability as well as my other household devices, and that the new modem is much more stable than the old.
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Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X