I’m new to mortgage refinance and would like some input

Current mortgage balance: $387,600 paying $2,800/mo.

Home worth estimate: $440-$450k

Current rate: 6.125% vs 30 year VA loan. I'm almost 4 years into the loan.

Offered rate: 5.4%

I'm estimating about $200/mo in savings, chatgpt is estimating closer to $280.

Is this rate a justified change? I know nothing about loan refinance and this is my first home. I've been told in the past to wait for a 1% drop or greater but I feel like I'm just gonna keep waiting and waiting due to the snail-like speed interest rates are decreasing.