Slow backup -especially deleting unwanted files and creating of bug report

Thank you for spending time answering my post. I have made a new run, this time it finished after 2h50m. I have copied from Livelog, profiling. Some sql-statements are using a lot of time, e.g.

Mar 7, 2018 11:55 PM: ExecuteScalarInt64: SELECT COUNT(*) FROM "Block" WHERE "Size" > ? took 00:32:39.989
UNION SELECT DISTINCT "ID" FROM "Block", "BlocklistHash" WHERE "Block"."Hash" = "BlocklistHash"."Hash")

Mar 8, 2018 1:25 AM: ExecuteNonQuery: INSERT INTO "DeletedBlock" ("Hash", "Size", "VolumeID") SELECT "Hash", "Size", "VolumeID" FROM "Block" WHERE "ID" NOT IN (SELECT DISTINCT "BlockID" AS "BlockID" FROM "BlocksetEntry" UNION SELECT DISTINCT "ID" FROM "Block", "BlocklistHash" WHERE "Block"."Hash" = "BlocklistHash"."Hash") took 00:41:11.000

The rest of the log is here:
https://pastebin.com/06BWh3Hw