Safari the vast majority of the time. I don't know the specific technical details but once in a while it doesn't handle something gracefully. Then Chrome. In terms of resource use I think Safari is considerably more efficient than Chrome.
Just switched to Brave (for personal surfing). It’s much faster and more secure. On my work “PC” I use Edge. If I use Mac for work I stick with Chrome.
Firefox daily driver. Then, depending on mood, Edge or Safari. Safari's supposed security benefits seem to be their justification for a lack of useful add-ons, but I don't see it. Looks more like usual Apple proprietary over-lording.
I've used Firefox for years because of its breadth of customization, security and excellent bookmark management. Whenever I try another browser, I always come back.