Ubuntu 24.04 windows freezing/cannot open

I have new Dell Pro Max 14 MC14250. I installed Ubuntu 24.04 and now I face strange issue. When I open some window for the first time (browser, IDE, Slack ...), it just does not open for a long time. It finally opens in a few minutes, and then all subsequent openings are just instant. Also, form time to time, it freezes again, even when in use. Can somebody advise, how to solve this issue? I have top-tier laptop, so this is definitely not caused by low-end hardware. Thank you.

Note: Classic Ubuntu (no-custom) install, so I am testing this basically in clean install.