@ian-coog Not really, clarification: by "later" I meant any period between the same day, a day later or even later.
The problem is after the 3 minutes of waiting the browser interface operation stays slow forever. And the tabs aren't even loaded nor pursue any process, they're just visually listed in the tab bar.
Vivaldi simply can't deal with many tabs.
PS. I created this topic to verify whether other people have the same issue or is it just me. And if other people have the same issue I hope my topic serves as acknowledgement for Vivaldi team if they're not aware of this already, that there are tab power users whose needs aren't being attended by the browser currently.