Tor browser inherently uses tor, as the other comment says, Mulvad offers tor browser sans tor as Mulvad browser. As per the "do you tor over VPN" issue I think we need to first cover some networking concepts...

So your internet works via protocols, UDP provides a basic connection where you can send unordered messages, TCP works on top of UDP to provide linear order. Things like old video chat and bittorrent work over UDP because you don't care about order, you just want the data as you get it, so the video freezes or glitches, but you get the most recent frame of the video. Things like programs and webpages aren't YOLO about data integrity, so they use TCP which enforces order, so you don't get frames from 1 minute later in your Netflix video out of sync. VPNs provide UDP, which is lower level than TCP, which tor provides, so you can tor over VPN but you cannot VPN over tor.

If you use Mulvad browser from your VPN, you will look like everyone using Mulvad browser from your VPN exit point, which may well just be you, it's fairly esoteric. If you use tor browser, you will appear to be exiting from a tor exit node along with hundreds if not thousands of other tor browser users.

[edit: just realized I forgot to actually address the is it worse to tor over vpn question. There is no privacy impact per you and the site, the question is state surveillance. Mentaloutlaw on Odysee says the feds will extra look at things if you tor from a VPN, but I really don't buy that's how anything works, I think most non-Germany state actors would look at ISP-level tor use to lock you up and not deal with the headache of subpoenaing a VPN provider to find out one rando is using tor]