I had to look up TI-99/4A. Are there still TV sets today you could connect this to?
Older LCDs will probably have RCA inputs though they might not work with all retro computing stuff as the signals are sometimes rather “non standard” (not sure about this particular case).
CRT TV should be fine, as they’re from the right era and a bit less fussy about signals.
Or, buy a DIN plug and make a cable that brings out the composite signal: https://99er.net/TIvideoadapter.htm
I haven't bought a new TV recently, but there seems to be no shortage of composite inputs on the sets I've been using.