Here are the following amps that have a track record of good synergy with Dynaudio; Naim, Belles, Simaudio, Hegel, Plinius and Octave ( tube ). Dynaudio need current to come alive and sound their best. The 3.4le are 86db, 4 ohms and rated up to 270 watts/channel into an 8 ohm load. So conceivably that would be 540 watts into 4 ohms if your amp doubled down.....indicative of the power they can handle. Obviously your room size, musical genre tastes, etc will dictate.
Of the above recommendations, the Coda is the best choice imo. I've never heard it, but it seems to have the power ( watts + current ). Low power tube amps will not be the best choice. If you go with a tube integrated look at Octave as they have the current necessary for the Dyns. The pairing is often used at Audio Shows. Good luck and take your time. Do plenty of research and audition as much as you can. Best......