Update Theme Nollie

after the advent of WordPress 5.5.1 the Nollie theme stopped working almost 50%.
How to fix this?

I see that the last update of the topic is from 2018. Will there be a new one or is the topic stopped for updates?

I would suggest reaching out to the author @muffingroup on their forum or by direct message - they should be able to tell you if they plan on updating this theme: