I watched Knight's & Magic. Here are my thoughts:
This anime is about a geeky programmer who gets isekai'd into a fantasy world where he is transformed into an androgynous mecha-fanatic (inb4: wow he's literally me!). The isekai world is like a medieval fantasy setting but with mechs added. Basically, this is a typical isekai show but with a lot of mecha-related content. If you stripped away the mecha theme, this would be an utterly generic medieval isekai. The mecha theme in a medieval setting is the only thing this anime has going for it – there really isn't any other selling point. In general this show feels fun and self-aware of its own silliness.
After the first couple episodes I was feeling cautiously optimistic about this anime, but as I progressed further my enthusiasm declined. I wanted to like this but the actual story is quite dull and boring. The story feels better suited for an LN instead of anime, which isn't surprising since this is an LN adaptation. A large portion of the show consists of the MC tinkering around in the mech mechanic shop, which could be interesting but the execution is so underwhelming (it's probably cooler in literature format). This issue is aggravated by the mechs functioning via some kind of nonsensical magic that isn't ever adequately explained. I think all the tinkering and mechanic shop scenes would have been way more interesting if the mechs operated on physical principles, or at least all the engineering aspects were coherently explained. Anyway, when the mech conflicts do occur they feel totally formulaic. This anime fails to deliver any kind of engaging storyline, and the episodes feel like a slog to get through as a result. I never felt the slightest flicker of excitement or suspense while watching this. It should be noted that I haven't read the LN and can't vouch for the quality of the source material nor the fidelity of this adaptation.
The characters themselves are rather lackluster; nobody is memorable in any way besides the MC. The supporting cast is tropey, generic, and underdeveloped. I liked the MC though – he was fun and his enthusiasm for mechs was infectious. The MC's VA suited him well, and his clingy female companion (Adeltrud) has some cute voicework too. There are all sorts of bastardized western-Continental-European names for everything that are a neverending source of amusement when paired with the Japanese dialogue in this ridiculous show.
Some of the action scenes are decent, although a little crude at times. This is hardly a high-budget blockbuster movie; CG is frequently used to animate the mechs and monsters. Don't go into this anime expecting mindblowing action scenes, you won't get that here. However, some of the mechs are pretty cool, and there's a decent variety of mech models featured in the show. Furthermore, sometimes the setting looks nice; for example, the medieval castles have a lot of aesthetic moments.
Although the OST is nothing special from a musical perspective, it has a unique medieval flavour that suited the setting well (think historic-European instruments like bagpipes and various types of horns). It is a comical juxtaposition to hear music like that playing while the screen is filled with mechs battling.
You probably won't be surprised to hear that this show can be fairly juvenile and generally feels catered to a young audience.
My personal overall rating: 4/10
Were it not for the mecha theme, this would be a boring formulaic medieval isekai. The story in this is not compelling or interesting at all. Most of the characters are underdeveloped and tropey, with the exception of the MC who is fun and likeable. The show in general is fun and playful, and feels like it isn't meant to be taken seriously even though it involves military conflict. There is a ton of 'mech fanservice' in this, and for diehard mecha fans it might be worth watching. Aside from the cool mecha action, I didn't particularly enjoy this anime.
The thing I savoured most about this show was the action scenes, but that's more a consequence of the story, characters, and script all sucking. If you just want to chill out and watch mechs fight in medieval castles and shoot lasers at each other, this show is fine for that. Honestly, you won't miss out on much if you just skip all the duller dialogue-heavy scenes. This isn't an anime you should take seriously.
I'm probably the wrong audience for this. For diehard mecha fans, I think this show is worth a try. Also, boys around roughly preteen age might enjoy this anime.