One of these powered by the psu to the pi. It does shut down octoprint when you power off the machine so you will have to wait a minute before printing anything.
I use a cheap adjustable buck converter from Amazon to provide 5V on one of my printers. It powers a bunch of RGB LEDs.
It seems reliable enough, in that it's been driving these LEDs 24x7 for over a year. I looked at the output on a scope once and I recall the noise being fairly insignificant.
Lots of people use these, or similar, to power Pi's.
Here's what I bought: https://www.amazon.com/gp/product/B07WQJ2GD6
not directly, you need a buck converter to step the voltage down from 24v to 12v.
amazon sells them in 5-10 packs or so for about $1.50 per unit.
https://www.amazon.com/gp/product/B07WQJ2GD6/ref=ox_sc_saved_title_1?smid=A3JJM7S8SDXVXM&psc=1
these are the ones I got for the fan swap for my printer
PI mount: This was a pain, I used a post found on thingiverse; and bought what I thought were the exact buck converter with the digital display. The ones I purchased were not the same size so I had to recreate it in Fusion 360 from scratch. Not sure I'm going to use it with having the octopus having the UART connections. But have it for back up or other uses.
Mine Remix: https://www.thingiverse.com/thing:5254029
My Buck Converter: Valefod 3 Pack LM2596 DC to DC Voltage Regulator 4-40V to 1.5-35V Buck Converter with LED Display
https://www.amazon.com/gp/product/B07WQJ2GD6/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
Original Thingiverse post by TGJONES: https://www.thingiverse.com/thing:4901983/comments
Are you using the Octopus or SKR to power your PI?
Yeah, I didn’t trust the ones with no read outs, these work great.
Valefod 3 Pack LM2596 DC to DC... https://www.amazon.com/dp/B07WQJ2GD6?ref=ppx_pop_mob_ap_share
Valefod 3 Pack LM2596 DC to DC Voltage Regulator 4-40V to 1.5-35V Buck Converter with LED Display https://www.amazon.com/dp/B07WQJ2GD6/ref=cm_sw_r_cp_api_glt_fabc_MKZ5STSP92WBTZ00Y93P
how many amps is the power brick and how many usb ports and fans will you have
you could also use a buck converter https://www.amazon.com/Valefod-Voltage-Regulator-1-5-35V-Converter/dp/B07WQJ2GD6/ref=sr_1_1_sspa?dchild=1&keywords=buck+converter+19.5v+to+12v&qid=161696 this will lower the voltage
i have these in my cart right now - https://www.amazon.com/gp/product/B07WQJ2GD6/ref=ox_sc_act_title_1?smid=A3JJM7S8SDXVXM&psc=1, sounds exactly like the one you got.
for the hot end i got these https://www.amazon.com/gp/product/B07WGXBZZZ/ref=ox_sc_act_title_5?smid=A2QQQKMKGVNA5E&psc=1 to try out.
and as another "quality of life" upgrade, i got me one of these so i don't have to fiddle with the microsd card - https://www.amazon.com/gp/product/B07WLKLTTY/ref=ox_sc_act_title_8?smid=A3OULB8S2H76BD&psc=1