Hi.
Quite a few complain their TV has problems with the ZX81.
I stumbled over this 5.5" TV as a kit on AliExpress. It has both antenna and video input.
Maybe that could be a solution for some.
3 different sellers.
https://a.aliexpress.com/_m0BULnE
https://a.aliexpress.com/_mKzJ6mM
https://a.aliexpress.com/_mrZukic
5.5" B/W TV as a kit
Re: 5.5" B/W TV as a kit
Hackaday had an interesting article about a similar kit and a video link to someone building the kit. The link is https://hackaday.com/2022/02/09/build-your-own-crt-tv/
2X Timex Sinclair 1000, ZX81, ZX80Core, 5X 16K Ram Pack, ZXBlast, ZX P file to Ear Input Signal Converter, Elf II
Re: 5.5" B/W TV as a kit
Maybe not the best beginner project as it might have up 20000 Volt, which can kill you on a bad day.