Just to clarify some statistics.
Before the Covid-19 pandemic:
Tourist arrivals from East Asia; 68.5% of total arrivals, of these, 40% was Chinese, meaning roughly 60% of the total East Asia arrivals was from other East Asian countries with Malaysia in the lead.
Tourist arrivals from Europe; 20% of total arrivals.
Contrary to what many thinks, Chinese stayed on average 7.76 days and spent on average 6,334 Baht/day, which is more than the 4,258 Baht/day that European spent, although the Europeans stayed on average 17 days. At least that is what the Thai statistics say.
Source: http://statbbi.nso.go.th/staticreport/page/sector/en/17.aspx