I have four UPS in my office. The one I trust the most is this one from CyberPower. I would not get hung up on brand. Any reputable brand such as APC, CyberPower and such will be good enough. You are correct in being concerned about Sinewave output. I had to discuss my needs with a CyberPower tech support engineer when I noticed odd issues with my 1000w Gaming PCs. It was he who stated that the non Sinewave models such as my model EC850LCD were not designed for switch power supplies.
But before you go spending all that money. Buy a cheap power meter first to ensure you understand your power needs. CyberPower and APC have power calculators on their website but there is no substitute for doing your own measurements. Here’s a recent topic on Power consumption with some recommendations for cheap power meters. X1C Drying mode and power consumption - #3 by Olias