Depending on what you have, a wildcard option could be Web content filtering - Microsoft Defender for Endpoint | Microsoft Learn - It requires some high-level Microsoft 365 licensing (A5 or other specifics) but if you already have that, then you could give it a shot without shelling out anymore.
Its not education specific, so its a more set and forget filter than something a teacher can tweak lesson by lesson, the other suggestions made above will work much better for that, but you can make use of categories and you can make exceptions - its basic, but if your already paying for it, its worth testing to see if it fits your needs.
Outside of that, Senso is a good product, much like Impero and LanSchool, just another flavour.