I do not want to close the tabs. I still needed them. I just want the browser to reopen with all the tabs and workspaces held there, dormant unless I reload them.

I'm a long-time Firefox user returning to Opera after >20 years. Firefox has this feature as standard - when opening the browser, the tabs don't load until opened.
I typically have half-done tasks with 100-500 tabs to keep, in up to a dozen work categories, and I'm on limited internet (50GB/month).

I've so far loaded Opera with a half dozen tabs and discovered it reloads all of them at opening, even in other workspaces. If this happened with hundreds of tabs, my internet would be used up quickly, and probably the memory wouldn't cope either.

I've been searching for this and I think I've discovered that Opera used to have Delayed or 'Lazy' loading of background tabs, but the setting is no longer there since 3023. Is that right? Is there no way to keep tabs open at startup without auto-reloading?