Since you are based in Germany and building these in May, you have a distinct advantage: you are in the hub of European electronics (with access to Aisler, Mouser, and DigiKey DE) and precision engineering.
For 7 units (including 2 variants for different prop sizes), here is your localized cost estimate in Euros (€) including German VAT (19%) and shipping.
You should use Aisler.net (based in Germany/Netherlands). They are the gold standard for prototypes in the EU. They offer "Beautiful Boards" and can even source your components through their "Simple Supply" service.
PCBs (7-10 units): ~€25.00 (Standard 2-layer, 2-day manufacturing).
Components (per unit): ~€35.00.
LED: Cree XHP50.3 or similar (available via Mouser.de).
MCU: RP2040 or STM32 (Mouser has a Germany-based warehouse/distribution flow).
Shipping: Mouser/DigiKey offer free shipping to Germany on orders over €50.
Since you need two sizes (e.g., a "Small" for 20mm tips and a "Large" for 30mm tips) and they need to be rugged, CNC aluminum is your best bet.
CNC Service (InstaWerk or Protolabs DE): These services allow you to upload a STEP file for an instant quote. For a batch of 7 custom aluminum "sleeves" with threading:
Cost: ~€300.00 – €450.00 total for the batch