I'd agree with what KGIII said in his blog
> So, what is the best Linux distro?
>
> There isn’t one.
We can all conclude what's best for us in a particular circumstance, but that won't fit all use-cases anyway.
For me my default platforms are Debian & Ubuntu (where I see Lubuntu as just a Ubuntu system anyway; just a different DE)
There are times when I opt for Debian (probably my default goto distro), but there are other times where I'll use Ubuntu (likely my close second).
As for what's best for you - only you can decide.
What made you use Linux Mint anyway will provide some clues? Linux Mint is the Ubuntu system with an extra layer of software added (runtime adjustments) as the devs don't have write access to Ubuntu repositories and the adjustments [hack] is less costly than creating their own packages for everything. Yes Linux Mint is visually appealing, but it's at a cost of Security - ie. you chose Visuals over Security with that decision; so it's those decisions that matter - of which we have no idea what's right for you.
If you're going with Debian or Ubuntu based (you specifically mentioned two Ubuntu based), compare what they do to the Debian or Ubuntu system (what they improve) and what they lose (such as security with your Linux Mint choice). Neither of Zorin/Pop have Security teams; Zorin use the Ubuntu kernels (ie. vetted by Ubuntu Security Team), but Pop OS doesn't benefit from that fully etc...
I'd struggle to think of reasons I'd replace Ubuntu with a Ubuntu based system (though there are likely use-cases where I'd opt for something; as if the box is off-line - security doesn't matter!), but Ubuntu sure isn't my only OS (but most others I'd consider don't meet your Debian/Ubuntu requirement)
FYI: The security hit Linux Mint & others suffers is still somewhat under your control (by settings etc - check them post-install!); though the effect of the runtime adjustments cannot be mitigated; it's not a huge worry in my opinion - but still a consideration being my point (ie. every benefit has costs; weigh those up to work out what's right for you).
