Opinion on browser zoom

Hey there!

For a while now I have been fiddling with my own design of GP and have progressed quite a bit.
The thing that has been bothering me for a while now is that I have mainly been working with a 133%-170% zoom level in Firefox using a 28'' 4K screen with a WQHD resolution enabled and a 24'' Full HD screen. On both the website, so the homepage and the according subpages look all right - at 133% that is, although I would rather let them be displayed at a 150% zoom level. On the 4k 28'' screen at WQHD or 4K even 133% look quite small.
Of course once you go to 100% most items will look even smaller which I noticed once I used a different PC/screen/resolution - call it a late newbie discovery.

Now my question is: What is the best way to go? Do I just enlarge everything to reach a certain kind of ratio and if so - what would be the best way to do it?
Or should I just stick to the assumption that most users' browsers will be zoomed in by default anyway like they mentioned here: https://graphicdesign.stackexchange.com/questions/38316/how-do-you-handle-clients-browser-zoom

These days there is an increasing amount of WQHD and 4K screens out there so should that influence my design decision?
I have reached a bit of an impass since have already put a substantial amount of time into the current look but feel like the homepage etc. elements should definitely be enlarged if the standard zoom level is around 100%.

So I am kind of appealing to your experience as web programmers/designers.

What do you think?