Drug testing is mostly limited (for civilians) to those with access to sensitive, secret, or TS information. In those orgs, you have higher odds of being drug tested as a contractor in the same team than as a federal civilian.

Regarding pay, it's actually pretty bad. A typical IT worker will be a GS-11 to GS-13 depending on location and degree (possibly lower in some locations, maybe higher in some high COL areas). GS-13 in many places is restricted to management and SMEs, though they're bumping up a lot of the "working level" grades because they realize they can't compete in hiring.

To pick a high COL area where you might find GS-13 working level IT folks, San Diego GS-13's max out at $153k. If they're actually GS and not another pay system (has a different pay raise method but usually maps to some GS grades, like Acqdemo) then it takes 18 years to go from GS-13 Step 1 to GS-13 Step 10. Most likely they aren't starting at Step 1 in any grade, let's say they start at Step 4, then it's 12 years to max. Once maxed, they only get the general pay increase every year. There are few technical GS-14 positions (this is changing, but not rapidly) even in high COL areas so the only "promotion" option for many is to go from a GS-13 technical role to a GS-13 management role (same pay) and then leverage that into a GS-14 management or technical role, if someone dies and a position opens up. GS-15 technical roles are pretty rare.