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I had a similar experience when trying to hook up my xbox via wifi and found that splitting the frequencies to 2.4gzh and 5ghz and using one or the other resolved the issue for me @Walker
I'm not saying this is the solution to your issue but it's worth trying as some devices prefer one frequency over the other and or different wifi wireless channel.
Current Phone > Samsung Note 9 _512Gb > Model: SM-N960 Hybrid-Duos.
Samsung Gear s3 Frontier Watch.
It may also be worth, just skeeping the 5GHz channel between 36 and 48 (lower is often the better). If you have any slightly older devices designed primarily for the US market, this ensures they can actually see the router!
*If this works on channel 36 but you also have some newer higher bandwidth devices, it can be useful to move the channel up to 40 or 42. It slightly limits your old devices, but should give your newer high bandwidth devices a couple more "less used" channels to play with.