Last weekend I stayed at the 25hours Cologne and can confirm that they have indeed joined ALL. The points posted immediately after check-out, but I was unable to redeem points because the front desk's access to that part of Accor's IT system "doesn't work yet". As a Diamond, I got drinks vouchers only after I asked for them, and late check-out was granted until 2pm - I had asked for 3pm, which would have cost extra. So ALL in ALL, it was the typical Accor loyalty and IT experience
Breakfast was free for all hotel guests as part of a post-COVID-19 promotion. And it was a regular self-service buffet breakfast, which is allowed again in this part of Germany.