Commercial Fixed Wing
Air Traffic Control Developmental
Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance
Human Factors; Procedure; Staffing
These two aircraft were deviating south around a cell of weather; the ZZZ aircraft was in front of the ZZZ1 aircraft by a couple of miles and diverging. I was planning on descending the ZZZ1 as he was under the ZZZ and stepping the ZZZ aircraft down under the ZZZ1. Instead I descended the ZZZ aircraft to 320 and showed the altitude in the data block; immediately as I unkeyed I realized my mistake and told the ZZZ aircraft at FL410 to maintain FL410. He repeated my instruction and the data block never showed him leaving FL410. A couple seconds later the ZZZ aircraft reported that he had descended about 100 feet or so; but was now back up at FL410. I said Roger; the data block never showed any altitude other than FL410. Conflict alert never went off.I had been on position at the same sector as that is my only R side; a long time that day with weather deviations. Staffing has been kept purposely low due to COVID 19 and social distancing; however; staffing has been kept so low that we are working 1.5-2 hours on position every time which is tiring; especially during the summer with weather deviations. Breaks can only give you so much recovery towards the end of the day when it is constant issues with weather. Deviations are much more taxing mentally and sector XX is a small sector without the room to operate outside of pre-determined routes and procedures.Being a developmental with only one sector to return to is also mentally taxing. There is no coming back to a different change of pace; but just the same complex sector again and again. And with training frozen no hope of continuing on the horizon while we continue to work with skeleton crews and traffic and complexity continue to ramp up.
Center Controller reported an airborne conflict and cited staffing levels as a contributing factor.