That's why i said attach the stock to the existing buttplate. 🙃
(I don't know if it'll work without seeing the existing buttplate, but i've used both ICS and VFC folding stocks on my MP5s with 3D printed buttplates.)
It varies from site to site, but there are legal limits for full-auto and semi-auto. Some sites restrict semi-auto DMRs to ~1.8j* but allow bolt-actions up to 2.3j*. Other sites allow both at the higher limit, some consider DMRs in the same range as AEGs/full-autos.
*I may be wrong on these...
DMRs/snipers are allowed a higher power level for more range, but with a minimum engagement distance and semi-only.
Because getting full-auto'd @ ~2 joules is unkind.