And I guess Bluetooths 2.4Ghz is also an issue?
I suggest Googling that… as it will be unrelated to setting up your Blynk server/client anyhow… they will just use whatever network connection is available on the RPi.
Take away the WiFi and the ESP is just a smaller, faster MCU with more memory. But unless that stuff matters, then perhaps oldschool Arduino & 3g/4g modem? The Mega offers lots of RAM, 16MHz runs anything I have thrown at it and tons of IO.