This information is so deep hidden ...
26.1.1 was NOT the last version for windows 7. Please update your informationFrom the v28 (official build), it shipped with Qt 6 libs, thus you can't run it in old OS (newer kernel required).
info: https://github.com/obsproject/obs-studio/discussions/6481
Second limitation is described in this thread: https://obsproject.com/forum/threads/obs-will-not-open-after-installation.167410/
Also updated capture hooks may not work properly (Game Capture source of OBS).
Last version of OBS for Win7 was OBS v26.1.1, some details here: https://obsproject.com/forum/threads/win-7-ultimate-64-bit.166308/
exactly FOR it was. But of course you may able to run some later official builds of OBS in Win7. Or you can make custom build or most recent v29.1.326.1.1 was NOT the last version for windows 7. Please update your information