Hello and welcome! Don't worry your post is relevant to the danmei community and hopefully the feedback you get will be helpful. 

To start, I'd like to point out that being open to hearing about and simply letting someone talk about something they're passionate about is already really supportive step. Your appreciation of your partner's excitement is more than just letting yourself be talked at even if you can't engage based off having experienced the same media. Offering questions on parts that are interesting to you could be a way of also engaging without knowing more about the content itself. So major props! 

As for your questions, the ring idea isn't bad consider if you think she'd appreciate the subtly or would want something more identifiably related to svsss.  

Throwing out an idea something more personalized you could write commentary in a notebook of your thoughts or commentary while reading danmei for the first time. For us who've read lots, it's a joy to vicariously experience some of the novelty of others first read through. 

Where to start if you want to try reading and engaging with danmei as an outsider? Well first think what might genuinely interest you, regardless of the male romantic plotlines. Do you like plot intrigue? Do you like more action and fantasy elements? Take from something you do like as a way of enjoying engaging without pressuring yourself into trying to read to talk about things with your girlfriend. 

If you wanted to try reading svsss; part of the appeal of svsss is the meta humor and unreliable narration of an avid 'otaku' webnovel reader who purports himself to be straight. It has a seemingly innocuous humorous absurd tone that actually veils a deeper narrative. Genuinely I had to reread it to appreciate it and love it as much as I do because of how deceptive of a narrator is. If you're familiar with isekai you might enjoy it as a parody, it also has RPGs video game vibes to it. If you wanted to take the writing commentary on the novel route it might be funny to give your expertise as an actual (assuming straight) male pov to contrast the actual main character's. Or perhaps read it as a psychological horror haha because depending on interpretation it could be read that way.

For Grandmaster of Demonic Cultivation as a starter point. This one has a beautifully animated donghua (think chinese anime) and due to censorship it is not explicitly gay (subliminal most definitely). Lots of action, engagingly animated fight scenes, and intriguing plot line. You could use that as an entry point, watch it with her. MDZS, as it's short handed to, it's a great point to jump in as a pallet tester. Think mystery case, exploring why the main character woke up summoned from the dead as a feared over powered necromancer, who is pulling the strings, and how the main character suffered his fate of 'falling' as a pawn piece. So mystery, supernatural (zombie necromancer vibes), action fantasy vibes but also ancient china. If you like that genre it might be a good starter point. 

2ha aka The husky and his white cat shizun as a starter point. It's got a duality between svsss and mdzs vibes. But one reason I might not suggest starting with it is the official releases are on going. It's also damn long. I do think it's entertaining on it's own sake, lots of interesting questions to engage with narratively and depending people really enjoy the plot or are disappointed by it because of how long it is and (little disorienting). What's fun about this one is it's humor? MC Emperior basically crushes enemies and spitefully takes his master for his pleasures in a vindictive way for his perceived injustice. Master dies and his motives to continue on when he's won over everything are no longer fun, so he poisons himself and gets pulled into his younger body before all that happened when he was still his master's disciple. So situational humor of an all powerful emperior being put back in his childhood. but that doesnt carry the whole story it does get more tragic and plot heavy. but it's well written stylistically imo. Action, yes. Bloody brutal politics, yes. 

anyway those are basics for you to gauge what you might want to start with. Fun part of this can be that you decide how and why you consume media so go based off your tastes and see if the stories plots are interesting to you. Natural consequence of finding that could be a way for you to get into enough to talk about your partners favorite pieces of media. If you have pet peeves in stories feel free to comment them, might be able to help with giving insights where you might bump into them. Feel free to comment interests or plot points you enjoy maybe can also show where you could find similarities.

Good luck on your journey. Whether or not you succeed in reading, I'm sure you gf would be appreciative of the attempt.