Need help transitioning from P2p to P3p

I had a P2p running flawlessly with a MK3S+, primarily using P2PP but. A week ago, I got delivery of a P3p. Since then, I couldn't manage to get it working properly.

1) I struggle with the hardware. Filaments that I use a lot and without any issues in the P2p (PolyTerra, Filamentum Extrafill, Prusament, …) get broken down to pieces inside the P3p. Not along a slice, the pure filament. This happens mostly on the buffer entry or the roller before that, where it got mushed behind a few times now. But also the buffer exit to the outgoing tube happens to catch the cut edge. It seems that the two brass funnels have sharp edges and the path itself is too loose.

2) The few prints I tried from P2PP (worked perfectly with P2p, duplicated and adapted the config for the P3p according to the Wiki) all ended up with an unresponsive P3p: screen not responding, no filament produced, fan blowing on full, but, the local web interface was still responsive. When I cancel the prints there, it locks up, too.

3) So I got back to Canvas. I can't really use it, as my intended use will be offline, but I wanted to get things running. Again, the machine is calibrated well, and runs 24/7 standalone or with the P2p. Yet, with Canvas and the P3p the pings are off (~94-96%) and I get color shifting after a few splices.

4) When starting a print from Canvas, as soon as the SmartLoad shows up, the printer seems to execute an M600 (Filament change), which gets the whole SmartLoad out of sync.

5) Splice calibration is completely different from the P2p: while I could print most of my PLA perfectly fine with 000, I need completely different settings for every of my filaments with the P3p: I need -2 to +3 on temp depending on the brand and the Polyterra even need +3/-3/0 for a still quite brittle but smooth splice. Is the new splice core that different?

6) The P3p freezes up for no obvious reason, for example during splice tuning or when just idling.

7) The touchscreen does not work well at all. Scrolling items, ie. in settings, is absolutely impossible. Touching the right item is hit or miss and to have a touch registered, I have to press really strong. The P2p display was nothing to write home about, but at least it did its job.

What of those experiences is expected, and where should I start to get a working print?

Thanks for your help!