16:9 over composite

XIIIVampire

Pi 3b+
version 4.6.1

I have searched for answers everywhere for hours, & I almost messed up my video-out trying to fix this on my own, so I beseech your kind help.

I own a 16:9 CRT. As you know, when you output Retropie on HDMI, Retropie presumes the screen is 16:9 & scales Emulationstation accordingly, it also provides black bezels for games since they're historically 4:3. Providing these bezels lets games remain 4:3 on a 16:9 screen.

I cannot for the life of me figure out how to achieve the same functionality over composite to my 16:9 CRT. By functionality I mean that ES is scaled correctly just like HDMI, & games get black bezels (borders on the left & right to preserve 4:3) just like HDMI. Please help. What I have tried:

changing config.txt by adding "sdtv_aspect 3" (this fixed everything not Emulationstation or Retroarch related, specifically, the screen looks right during boot/login, & also in those bluescreen settings menus)
retropie > raspiconfig > advanced options > resolution -- changing to either "DMT Mode 85" or "82" requires reboot, upon which I get no image. I had to boot over HDMI to switch this back to "Default." Caused some fear in me.
retropie > retropie setup > configedit
retropie > retropie setup > emulationstation --- both of these didn't seem to have anything helpful.

If you only have a 4:3 CRT & would like to help me, I would guess that you'd see success if your left & right sides of the screen are trimmed. Or you'd see a squashed widescreen image fit into your 4:3 which my CRT can stretch. But like I mentioned above, config.txt sdtv_aspect 3 makes the lower level stuff look soooooo goooood, I know there must be a way to output true 16:9 over composite.

Thank you for your time!
~ Gizmo

Note: I would be totally happy whether the Pi outputs at at true 16:9 resolution or outputs a squashed 4:3 image which can be stretched to anamorphic 16:9, but of course the first option is better.

PS Sorry if I did anything wrong in writing this post, it is my first.