Orbi RBR350 behind ubee-ubc1318zg modem

For 6 months I am having an internet connection that frequently is disconnected. At that time I used a Ubee EVW321B (in bridge-modus) and TP-link Deco P9. The latter one was working as a cable modem as well as a wifi modem. Before this period it worked good with a stable internet connection but for some reason, the internet connection became very unstable. I tried a new cable splitter and new connection cables which were sent to me by the internet provider but this did not work. Therefore, I changed the TP-link for the Netgear Orbi RBR353 (Orbi RBR350 with 2 satellites) with the hope to get a better connection. Yet this was idle hope. I still had to restart the modem, router and all the other apparatus more than once a day. Finally, the internet provider change the Ubee mode for a newer one; the Ubee UBC1318ZG modem. The repairer from the provider also changed some other, older connection points and fixed a problem in our block Points-of-presence of the cable. This made the internet connection much better although I still had to restart the laptops, Mobi's etc once a day to keep the internet stable. To see if it was an issue for the internet provider I clicked a laptop directly on the modem and this gave a stable connection although the latency (ping) was on the slower side (more than 30 ms). When using the Ubee and Orbi together the connection became unstable again with latency between 20 and 800 ms and very frequently package losses of 100%. As this is only the case when the Orbi is connected to the Ubee I think it has something to do with the settings of the Orbi or the interaction between the Orbi and the Ubee. Does anyone recognise this problem or have a solution that could fix this unstable internet connection? That would be great. By the way, the Orbi has the latest firmware update. We are using both Windows 10/11 and macOS. Thanks  

Pieter-Jan