I never played the Venom twice got to step 6 from
freerolls and could not get in. But I have played many other big online mtts over the years.
Treat it like a regular game and enjoy your experience. Most important thing is you got to mentality remove the buyin from your decisions and try and make the right decisions.
There are multiple Day 1's I suggest not playing the the first one but play a later one that way you can scout what is happening on games e.g. what play is like at tables how much chips players that make it through have.
There is also a specific number of levels that are played every day 1 so you should easily know the start and end times. Adjust your schedule accordingly so that you have enough time to play it and that you are well rested and mentally prepared to go when the time comes.
Anything above $100 plays the same way. There will be a bunch of aggro and good players but this might have a few soft spots as there are many qualifiers some that got in for free.
Strategy wise should be same as a regular mtt. You base your strategy on your opponents and the cards you are dealt. Try to play the style you are most comfortable with. Always keenly observe table and make notes. Look for players to target and exploit.
I am a serial late register if i was playing it I would late register I am comfortable with starting with 30-50BB you might be different and starting from the beginning of tournament might be optimal. You want to try and play to our strengths.
I hope this helps
Best of luck