ISP Replaces SSL Certificates... Any Solution?

Solution 1:

No, proceeding is not safe; your ISP is performing a man-in-the-middle attack on your encrypted traffic, and can therefore read all traffic if they choose so.

Is there any solution for this

Yes: Get a new ISP.

As a side note:

I am very surprised; I have never heard of an ISP doing this, and I would not even consider such a company a proper ISP (since they don't provide the service of an ISP, which is sending and receiving the data that you send or want to receive).

What ISP is this? I can't imagine any regular ISP doing this.

Solution 2:

Get new ISP ok. But i get simple solution, use VPN. My ISP block site by injectng (replacing) SSL certificate, even with DoH/DoT. So i use VPN to bypass it.