It is usually pretty seamless, but unfortunately some laptops may have some weird quirks or certain things which may not work and may require manual steps. Most common issues you might come across is with suspend/resume - it's either broken, or it may not resume properly or may crash etc. Other issues could include audio issues, or wifi issues.

This isn't generally a problem though with popular / "good" models, as these get picked up and fixed pretty quickly. The problem usually is with less popular models, or brand new models which haven't been tested yet by the wider Linux community.

Good models/brands include Thinkpads, mainstream Dells (especially the XPS series), mainstream HP (especially the EliteBook series) and Framework. Plus there are laptops which come with Linux out-of-the-box, as the ones by System76 and Star Labs. HP also have the Dev One, and Dell have the XPS Developer Edition.

In general, I'd recommend going for a full AMD system (CPU+GPU) because of their better integrated GPU performance, particularly on Linux. Unlike nVidia, you don't need to install any proprietary drivers for AMD GPUs, which increases system stability and reliability - especially when you update your system.