If I pay more than 50% taxes within my salary in overseas Israel and the maximum tax in Thailand is 35%, will I be taxed based on the DTA? As I’m a higher rate taxpayer overseas, am I fully credited?

If it can be proven that the work was done overseas, and the salary is not from work conducted in Thailand, then you can justify that it is not liable for tax in Thailand. However, if the work was conducted whilst living and working in Thailand, then it is potentially taxable in Thailand.