On a second thought, now I see that we did visit a few SOTA summits on Azores.
On Faial, we visited CU/FA-001 Cabeço Gordo. There’s quite large radio tower on the top, and if i remember correctly, even has partly paved road leading all to the top. But it leads through active pastures with a lot of cows so i can’t say if you are allowed to drive there. We went by bus to the viewpoint Miradouro da Caldeira to the east from the summit, from where it is only a short hike to the top. From there we hiked along the crater rim and descended to the west partially along the access road.
On Sao Miguel, we visited two SOTA summits.
CU/SM-002 Pico da Barrosa is a simple drive-on summit. Paved road leads to the small parking, from there it is only a 200m or so walk to the summit. Only a few small towers there and a great view to the lake Lagoa do Fogo below. Plenty of space for an antenna.
Photo of our ride at the summit of Pico da Barrosa below.
At CU/SM-005 Pico das Eguas there’s a nice marked circular hiking route around the area (Serra Devassa trail, cca. 4 km), starting at the parking at the main road. Not much space, but has a trig point that could be suitable for attaching the antenna pole to it. No permanent towers there.
Hope it helps. Enjoy your stay there!