It's up to the website to manage this, not the browser.

2 things :

• 1st don't multi post it's not reddit here. I see you posts on all the channels.
• 2nd right click on the tab : pin this tab. Now you can close your browser and restart it keeping track of your video. If it doesn't work, it's caused by the website not the browser.

To expand on @misery_mansion@lemmy.world's post: unless you log on or enable cookies, it's very hard for the website you're using to track your video viewing behaviour. They could only guess who you are and where you paused the video. Providing such convenience is how they trick customers to allow tracking.

you can unload the tab with sideberry and with others extensions. If you just close the tab to save resources instead, simply unload it so you can quickly return to it and pick up where you left off.