Barrier can no longer be used with sidecar

[gzqx]

I don't really think it is caused by barrier, but discussing it on apple's side will definitely not work.........
I used to use barrier with sidecar 2 years ago when sidecar was just released, it worked fluently. (Linux as server, macbook as client, controll ipad through macbook)
Recently when I try to do it again, I find that when trying to connect to sidecar barrier connection immediately gain huge latency and loss.
Same router same device, got confused. Thinking that apple secretly nerfed it (I haven't update major number of macos for 2 years). Wondering if anyone is experiencing same problem?