You might find the 'multireddit' functionality useful - it combines multiple user-defined subreddits in to a single 'front page' to browse. For example, I follow the 'it_resources' multireddit created by another user -
https://www.reddit.com/user/neztach/m/it_resources/ . It's a useful combination of a lot of IT related subreddits across multiple areas - from networking, to system administration, to security etc. Of course, the challenge is finding suitable multireddits in the first place - /r/multihub contains lists of them, you might find it useful to have a look on there and sort by 'top', or to run a search on that subreddit for a term and sort by top.
The other strategy I can recommend is looking at related subreddits. So if you stumble across a 'good' subreddit that's interesting to you, have a look in the sidebar and see what other subreddits are suggested by the moderators of that subreddit. I find that to be a great way to find high quality related subreddits either with a narrower focus or just on generally related topic. For example, the /r/homelab subreddit recommends /r/networking, /r/sysadmin, /r/datacenter etc...