a similar game

BloodLust and its sequel are billed as spiritual successors (and they for sure get the graphic dynamic down), but they style more to an actiony, loot-heavy, classic RPG combat-based dungeon-crawling design, so don't go into the games expecting them to mirror VtMB too closely, especially as far as subtleties go. Still, if you ever thought VtMB would be more fun if it played out with more traditional RPG focus, or if your itch for anything remotely VtMB really needs a scratch, it's an option to consider. :)

Unfortunately, there hasn't yet been any other game (that I'm aware of) that quite attempted the same degree of freedom of approach and nuance of atmosphere that made VtMB so truly remarkable.

Mods in VtMB share the same resources, so they inherently conflict. Clan Quest is the only notable one that integrates other major mods, along with its reliable integration of whatever version of the unofficial patch is most recent [something other, no longer supported mods don't do] (all that on top of CQM being a notable mod in its own right). Once you install Clan Quest, you'll have the ability to toggle whichever of its integrated mods you prefer (though most of the integrated mods are goof-off ones or major revamps, so other than the two I recommended, they're mostly best left for spicing up the game after you've had a few standard playthroughs).

(I believe you can also just install CQM to activate the Unofficial Patch and Companion Mod without activating the CQM content, if desired.)

Inherently, Clan Quest (as per the name) was conceptualized as adding a single distinct quest line to each of the core clans, to make each individual clan playthrough more distinct. However, being that the game released in 2004 and CQM is still being updated, there've been a lot of further additions since. (Side-note: Unofficial Patch+ [the expanded content version of the Unofficial Patch] is, I believe, still being updated as well, but later additions to the + option really screwed with certain clan and balance dynamics, so it's among the mods I wouldn't recommend for starter mod use; At the very least, you won't want to use it while playing Tremere, as it gives them Ventrue's Dominate dialogues, which makes Ventrue's playthrough meaninglessly indistinct.)
It's been a while, so unfortunately I forget if you can safely hot-mod the game without breaking save files.

With those two elements in consideration, and the fact that VtMB's core infrastructure is rather unstable, I'd say that starting a fresh run would definitely be the more recommendable option. Especially so given the likelihood that- if nothing else- there's a good chance that certain CQM quest triggers are tied to story events, meaning progression is liable to bug out.

You can download Clan Quest Mod (which includes all core mods and patches) here. Once you've burnt out on what CQM has to offer, moddb also hosts most of the other major VtMB mods [though, as I noted, you'll need to first uninstall CQM to utilize those mods, due to how mods overwrite one another, bugging the game out].

While other mods are oriented more toward changing the game experience, CQM and the unofficial patch+ are oriented more toward enhancing what is already there with additional content matching to the core style of the game (with the UP+ actually restoring several unfinished areas of the game). They're easily recommendable for any player of the game, as they give a more full experience without significantly changing the atmosphere or playstyle.
Companion Mod and the Rage mod are obviously oriented more toward changing, but they're valuable in providing PnP-appropriate distinction to the two clans that are in greatest need of being fleshed out, both for the sake of better reflecting their PnP dynamic and for the sake of being more distinct from Ventrue and Brujah, respectively.

I was just thinking back of when I've bought the physical copy.. It was not much more expensive than now. ( +12 years ago)
Thanks 🐱