On my travels around Israel in November of 2019, I stopped by Bet Alpha National Park, which ended up one of my favorite ancient sites in the country (including many places that are already inscribed as WH sites).
Bet Alpha must be the smallest of all national parks in Israel - it is basically a single room of the ancient synagogue headlined by the primitive yet evocative mosaics on the floor. The 15-minute interpretive video – which started as soon as I entered the room, since I was the only visitor at the time – is a lighthearted dramatization of the origin of the mosaics, mixed int with an overview of the synagogue architectural features. It is definitely worth the time to see and listen to; as the explanations cover different parts of the mosaic, those components are lighted on the floor. After the movie ended, I had a few minutes to look over the mosaic and the remains of columns and supports under the full lighting.
The cost of the entry is but a few dollars, and if you have the "orange card" Israel Pass (which allows entry to almost every national park once within the space of two weeks) there is no additional cost. No guidance is needed for the visit, which in my case lasted less than half an hour.
The rest of the synagogues on this tentative submission are clustered near Tzfat or by the northern shore of Lake Kinneret. I was close by only on intraday basis and did not find time to stop by them, but I assume that if you are staying in the area, you can cover most if not all of them in a matter of less than a day.