I think the suggestion of an HPF is probably a good. I would put it first in the chain, not last. Why have your compressor going crazy over low end that isn't going to be there later on? Why try to take out tubbiness with EQ when the HPF should be doing most of that? Etc...
To set up, while playing, gradually increase the cutoff frequency until the bass thins out too much. Then back it off a bit until it sounds full enough.
Granted, the X32 has an adjustable high pass on every channel, so you could just use that, at least as a start. Somewhere between 35-100 Hz is probably a good place to start.
You could also probably benefit from a nice parametric or semi-parametric EQ, 1-3+ bands. The X32 also has this, but you might find it beneficial to have a nice analog one at your feet that you can adjust quickly and easily. I have a Carl Martin 3 band that is really nice. I think it's BBE that makes an Ampeg style tone stack pedal, that may do the trick too. I would probably start by trying a modest but ideally narrow cut somewhere in the 50-120 Hz range. There's also a strong possibility the band PA may have certain frequencies that are more boomy than others, especially in certain rooms. The key is to take out enough of the offending frequency to avoid that tubbiness, but not so much that you lose the power of the low end. It's a balancing act, but if you find the right frequency, width, and amount of cut, it shouldn't feel like you're missing anything, just cleaning up the sound. You can also push the overall bass level to compensate.
And then a good compressor probably makes sense. I really like my MarkBass Compressore. Studio style tube compressor pedal. it's got all the normal "studio" compressor controls, so you can do anything from super subtle to squash city.
Now, for practicality, you probably want to have the SansAmp last in your chain to use as a DI, but from a signal chain and processing standpoint, I would do bass, HPF, SansAmp, EQ, compressor (and then just any generic DI should be fine as long as it's not noisy). I would start with what you have now, just plugged into the SansAmp into the mixer, and then try some of the suggested processing at the mixer level, and also explore the possibility that the PA subs need to be EQ'd a bit. if you run a sine wave generator through the subs, you should be able to step through notes from 30 to 100 Hz or so without any particular note or notes overtaking the room. If they do, those frequencies need to be tamed and that should be happening at the system level, since it will also affect kick, any lower end keyboard sounds, potentially the low end of guitars, etc... This is also likely to change depending on where you are in the room, so walk around with the ipad and try to find a happy medium everywhere (but with the main focus being center mass of the audience area).
The HX Stomp would not be a bad choice, and that way you could have presets to simply recall. BUT, it will take a fair amount of programming and that does not come naturally to everyone. And there's a certain vibe to just using nice analog processing vs modeling. The advantage of the modeling is preset recall and flexibility. One thing to keep in mind, is that air is what makes sound sound good. You are kind of bypassing that with either the HX or especially the SansAmp (where the cab simulation is more of a "also included" component than the main focus). With the HX at least you can try a zillion different impulse responses to find something that sounds good with your setup. if you are dedicated to the ampless lifestyle ("not that there's anything wrong with that!" says Jerry), you may want to consider a proper dedicated cab simulator, especially if you're playing more "vintage" style music where a bass direct into a full range PA is not really the vibe. As an example signal chain, an dedicated cab HPF, SansAmp, nice analog EQ, analog compressor, dedicsim, would be fairly simple but also pretty flexible and yield about the best results you could probably get going ampless. Which of course by that point you've spent like $1k maybe and probably could have just gotten a PF-20 and a nice single 12 or 15 cab, and just sounded like a bass into a tube amp into a full range cab instead trying to recreate that with... other stuff.
