Earlier quoted context omitted.
Same here, currently sitting at 300 tabs ( Lost about 800 a few weeks ago from Safari crash again ). I just wish the Show All tabs on Safari put up a list of tabs so I could quickly navigate through them ( and selectively close them ). Right now Show All Tabs Reloads all the tabs. That is the same on macOS and iOS. Your phone gets quite warm doing it.
Safari maintains a list of tabs in a plist. You can’t delete while Safari is running, but at least you can extract the list to back it up.
Firefox used to have similar problem with their json so after a few bug report with them they fixed it with another json.bak as redundancy. ( The good days of Firefox )