I run my backups like this:

    OUT="${i}.sql.zst"
    PART="${OUT}.part"
    sqlite3 -readonly "${i}" .dump | zstd --fast --rsyncable -v -o "${PART}" -
    mv "${PART}" "${OUT}"

That doesn't block writers (when the writer uses WAL), and gives me a dump that's compressed well while also being easy to sync. My Home Assistant DB is 1.8GB, my dump is 286MB compressed, and I'd guess 90% of that is consistent from one day to the next.