You can also try International Health center in the Hague, when i discussed that with my huisarts to be referred to Wetering Center in Amsterdam, she said there is a good gyneacologist at the Health center itself (Belgian or German) who was specialised in infertility/subfertility and actually could do it in the future if I would proceeed. I feel your frustration, i am in the same shoes, a long story .Good luck!
When I was checking for the same I also found a contact of a doctor (he seems to use to work at one of the Asmterdam centers such as Wetering) but he has a praktijk in Haarlem. I contacted him per email at that moment when i considered to do a protocal remotely. https://www.echocentrum-haarlem.nl/contact.php; email: firstname.lastname@example.org Try to contact him but I have no clue how good he is.
If you can try to contact Medilca Center Wetering in Amsterdam if you have a referral letter from gynecologist /huisarts. I am from the Hague (expat/you can drop me a message here). In that center they do follicle development monitoring as well I believe, I was th for endometrium check before the transfer abroad, before corona. They asked though a digital letter via a special system to be sent by a huisarts (mine is at International health center and they did it for me).