As you’ve found out, you can’t use recordings for sound checks. Live vocals and instruments interact with the acoustic properties of the venue quite differently than just coming from speakers. The smaller the venue, the more the difference will be. You might get away with it in a stadium where the live sound barely reaches the audience. Do your sound checks live. After each gig, save the settings to scenes and use these as starting points for similar venues.
Thank you for clarification.
What I would like to know is
The reason behind the tonal difference
Because I have set everything the same
And nothing was touched.
Gain, eq, main out, monitor out
Everything remained the same
And these goes through the same system
As well as same preamp to same fader.
Please check where in the signal path you were recording from.
For virtual soundcheck, I would recommend setting the direct out to ‘Post Preamp’ in the routing screen, and ensuring you are recording ‘Direct Outs’ in ‘Setup > I/O Patch > USB Audio’.
As garyh said, there are other things like the acoustic (unamplified) sound to consider, but the sound going through the PA shouldn’t be as different as you seem to be describing.
As stated by Gary, the difference is that with the virtual soundcheck you hear only sound from the speakers while listening to live sound sources on stage AND sound coming from the PA is a blend of two sources with the inherent differences in time arrivals/reflections and the attendant phase relationships.
The only time when a recording for sound check might work is when there are no vocalists and all instruments are electronic with direct ins and no amps.
For this purpose you need to be recording the unprocessed audio then process it when you play it back.
If you record it after processing, then apply the same processing again it will sound very different - all eq cuts & boosts will be doubled etc.
You’ve still got the direct acoustic sound from the stage, which will not be there when you play back, but there’s no getting around that.