How can I safely get power strip to desk in center of room?
Appliance and extension cords are called cordage.
Use the right stuff
The issue with cordage as a substitute for permanent wiring of the structure is not a “don’t do it” issue: it’s a “use the right stuff” issue.
“The right stuff” is appropriate wires designed for permanent use in structures, including appropriate physical protection.  For instance instead of stapling cordage to a wall, you should use surface conduit with THHN wires inside.
Of course, that requires a transition from the THHN to the cordage at some point.  That happens at a junction box, e.g. with a receptacle in it; the easiest way to transition from hardwiring to cordage.
Consider a pendant for center-of-room power
A pendant is a piece of special cordage with high quality strain relief on both ends (think the Chinese finger puzzle webbing) that drops straight down from a box on the ceiling down to a junction box suspended in midair by the cordage.  You then plug into that recep.
Probably best to use a fan-rated ceiling box.  This can be a surface-mount box (you’ll need to find the studs) which in turn can be supplied via surface conduit such as Legrand Wiremold.
The suspended box would probably be a metal box rated for a fan, since they are tough and built to endure tugs on the pendant.
If you want to be very fancy, you can have the pendant lock into a locking connector like a NEMA L5-15.
That PC power supply is a terror
That “1200 watt” PC power supply is a gigantic beast made for gaming.  The “1200 watt” figure is the actually useful DC output of the supply; it is NOT the AC mains input — that is affected first by the efficiency of the unit and by the power factor.
   X (actual power drawn) x efficiency% x PF% = useful power out.  

The “850 watt” power supplies actually draw 10 amps. So I could see a 1200 watt supply drawing 16A or 17A.
I would revisit the necessity of such an ostentatiously large power supply.