@RegalPotoo @Wilshire good point. Release agents are used for casting concrete. They look to be oil and water mix so I'm guessing most plastics would be compatible.
Also has to be a clear path out for the print/concrete.

@LazaroFilm glad I didn't bother learning this then...

@PeleSpirit @topinambour_rex yes, you can. With a dual extruder printer. Or if pause the printer mid way through and change the filament, is recommend using a printer with filament detect, it should move to the side so your prints don't get damaged by the hotend.

@Piecemakers3Dprints @CaptainFlintlockFinn as a one time chemist I'd agree that there is a real possibility some trace materials in the resin causing some harm in prolonged contact. The resin may be set but could potentially leach some of the other materials such as unreacted ingredients, catalysts etc. In the same way that cheap jewellery can release alloying metals that cause irritation. A dermatologically safe varnish seems a sensible call.

@CaptainFlintlockFinn are those resin support marks? If so you could try reorienting your model to reduce the number of supports needed. Possibly experimenting with the number, spacing and thickness may get better results. I'm no expert but have found it helps sometimes.

@charmed_electron oh and proper personal protective equipment is must. I use decent mask that will remove solvents from sir.

@charmed_electron printer type and size depends on what you want. Consider the software to use on it, printers may only like some slices. I've found FDM and Resin printers to be complimentary. I'd agree with person about getting a suitable space. I use my loft, getting a place away from you main living space is needed. Temperature is an issue but settings can account for some of this.
I think of my FDM printer as mechanical tool to build things. My resin printer feels more like cooking!

@PeleSpirit good luck. I didn't regret it. Been lots of fun!

@parallax I can vouch for the Mars 3. To some extent it depends on what you are printing but 28mm miniatures are great.

@PeleSpirit 3D printing is fun but it can be a time sink. Consider how much done you can invest in this. If you want to push on with other things then POD may be best. If you want to have it as a tool in your bag, then buy one for sure.

One thing I would say about resin printers is they can't be left for long periods and are best cleaned and packed away if you aren't using them.

@KroninJ @joemansmoke oh and a set of files can be useful as well.
https://www.screwfix.com/p/magnusson-needle-file-set-5-1-2-6-pcs/4474v

@KroninJ I use something like theses. https://www.halfords.ie/motoring/tools/garage-equipment/garage-essentials/rolson-4-piece-pick-and-hook-set-340885.html
Useful for the small supports and difficult to reach ones.