What Makes For A Solid Environmental Sensor Monitor For Server Rooms?

TL;DR: What environmental monitoring system do you currently use? What do you wish it did differently - or that it doesn't already do?

Hi fellow sysadmins! For a while I've wanted an easy and simple way to monitor the temperature and humidity for my small server room (which is really just a "den" that has no business being called anything more than a big-ish closet, but happens to be the perfect size for a single four post rack). I looked around and couldn't really find any simple or affordable environmental sensor solutions for my basic needs. I mean, it is just a home lab full of old Dell PowerEdges from eBay, after all. I didn't really want to spend more than $100 on equipment. I wanted PoE and easy setup, and to access it over the internet from anywhere.

So a few months ago I decided to setup a little environmental monitoring system of my own and bought some sensor breakout boards and microcontrollers. I wanted to be alerted when it got too hot or too humid, or if the temperature or humidity rose rapidly. I also reeeeally wanted to see the history/trend over different periods of time. These servers have certainly thrown off the dynamics of heating and cooling in my tiny apartment over the last 7+ years and I thought it would be very interesting to finally visualize some real data for once. I've made some good progress. I'm alerting on static thresholds, and rate of change criteria. I can see trends on a graph, etc.

I am curious though - what do you look for in a good environmental sensor monitoring system? What systems do you currently use? Is there any functionality missing that you wish the systems you use have - beyond just simple threshold and rate of change monitoring/alerting? I am the only engineer at a very small MSP, so I don't really have people to bounce these types of ideas off of, or to ask these kinds of questions. I'm sorry if this is the wrong eh.. vibe for r/sysadmin. I'm just genuinely curious how I could improve my little home lab monitoring setup - and curious what the larger industrial systems that I don't really have the opportunity to touch or mess with offer, or don't offer.