Ecoflow Powerglow

Upgrading the heating of my house which “was” to include a Powerglow.

Bought a Joule triple coil cylinder to attend to my stove and also bought the Powerglow but the thread/sizeof/boss is just not compatible between the cylinder and the Powerglow.

The plumber says the Powerglow is European size and the cylinder is UK standard sizing, not only, the teeth/thread are different.
Researched as much as I could to find out that Ecoflow actually has an SKU for UK (PowerGlow-3.5kW-P3-UK or PowerGlow-3.5kW-P1-UK) instead of EU (PowerGlow-3.5kW-P3-EU) but can’t find it anywhere!

Plumber tried an adaptor from 2” to 1 1/2” but the 1 1/2 powerglow EU won’t screw in…

Anyone has ever encountered this challenge and have a solution?