Ring Alarm Base Station will not connect to wifi

Ring alarm base station refuses to connect via wifi. This is the case even when Ring BS is inches from wifi router. Using 2.4 band on newish 3-band TPlink router. Have rebooted and factory reset on all devices (fiber) modem, router, base station multiple times. Tried moving BS to guest network. No solution. The base station does connect via ethernet and using a cell phone hotspot. Also connects via cellular backup. Worked for hours with my ISP and tech support from TPLink(router). Both ISP and TPlink have identified the Ring BS as the problem. Several other wifi devices from other makers have no issues connecting to my network. It's just the Ring BS that won't connect. Ring Tech support, while supportive, have basically said it's either my ISP or my router. The ISP and TPlink ask the obvious question - are you having trouble with any of your other devices? The answer is no, no problems at all. They conclude it's an issue with the Ring BS. Ring suggested getting a different router like a Eero from Amazon. After spending many many hours over two months without a solution I'm asking the community to see if they have any ideas or possible solutions. Sure, the Ring BS works with the ethernet, but the goal is to use as advertised via wifi in my small home. Has anyone experienced these issues and found a cure? Have you had better luck with certain routers or making port setting adjustments? Thanks for your input.