Pams has a clock and run/reset input. I understand that you slave it to the Beatstep Pro but not sync them in any way (so you're not telling pams to restart when the BSP does). To do this, I'd suggest to set BSP's clock out to a rate of 24 pulses per quarter note (or PPQN) in the MIDI Control Centre. Faster clock rates between time-synched devices leads to a more stable clock down the line.
A quick look at the BSP manual says that since an update you can use a TRS to dual TS cable to get both a clock signal and a run signal out of the clock output (section 7.2). I haven't tested this, so do that at your own risk, but if I understand correctly, it'd sync out of the box with Pams (make sure to set run input to be assigned to run on Pams). Cable to use is not a standard stereo splitter but stereo to dual mono, like the Hosa YMM261.
(the manual only talks about a clock and run signal when BSP is used as slave, but on the Muffwiggler topic people say it also works when using BSP as main and Pams as slave https://modwiggler.com/forum/viewtopic.php?t=193133)