Let's ignore the reality that orbital data centres are bullshit for hundreds of reasons and assume ketamine boy can pull it off.
This site lists the sizes and masses of starlink satellites. I'm going to use the V2 full size specs. 40m^2 fully deployed and 1,250kg.
https://dishycentral.com/how-big-are-starlink-satellites
The orbital decay times for unboosted satellites with those specs at different altitudes are;
500km - 5.68 years
600km - 47.02 years
700km - 303.73 years
800km - 1,536.21 years
900km - 6,112.47 years
1,000km - 19,255.79 years
Orbital decay calculator here;
https://www.lizard-tail.com/isana/lab/orbital_decay/
Data centres at higher altitudes better be built to last because they are not coming back down any time soon.