Is there any good opensource software with gui to manage such databases/graphs? I guess Wikibase is an alternative, although not very user friendly

In contrast, pocketbase [0] was discussed two days ago, and there are many user-friendly alternatives for relational data [e.g. 1-4]

[0] https://news.ycombinator.com/item?id=38898934

[1] https://www.getgrist.com/

[2] https://nocodb.com/

[3] https://baserow.io/

[4] https://www.rowy.io/