Some links that could interest you:
The transponder “Philips 46”: https://www.internationalkeysupply.com/products/philps-46-chip-pcf7936aa-blank
Probably uses the NXP PCF7936 imobilizer transponder:
Link to datasheet: Here
or PCF7936AS__3851__C,1.pdf (165.9 KB)
I think it includes a lot of useful info that could help you in your quest with the Proxmark.
The CN900 mini I know from a car locksmith. It’s more of a “dumbed down” solution for less technical folks (so its a specialized device with its own pricetag - about 170$ - does pretty much everythibg for you, including cracking the encryption if compatible and applicable). IDK if it works for your purpose.
Also consider that immobilizer transponders are usually either in in a wedge format (bout 3mm thick, potted in reisin in a plastic shell), or in a something similar to an “x series” that is intented to be slotted into a glass mould (DO NOT IMPLANT THIS, NOT BIOSAFE, also pretty large).
Edit: I realize now that you probably don’t intend to implant this. but still, useful.