Hello,
My input on this subject: my recommendation goes the same way as Lyra cartridges designers- the AT33Mono. It is a true mono, not neutered stereo! People get confused because it has two true mono coils. (They are not stereo coils connected to run as mono - this is a cart designed as mono, not the usual stereo cart internally connected in mono, which is the neutered stereo/mono.)
So, Lyra's designer was saying (reportedly) when they interviewed him, he said that in case one cannot afford a Lyra mono, then he'd recommend the AT33Mono as it's the next thing that comes close to his Lyra to his ears.
I can second that it's a fantastic mono cart, and for folks considering a very much budget option, the AT3MONO little brother is pretty good as well, and performs quit above its price.
I have the anniversary edition, which is essentially a premium AT33MONO. It is not far off a Benz MC3, and is a perfect match for the ET-SUT (1:25 step up, 100R load LOMC).
The huge advantage of the AT33MONO is that it can plug into a stereo system, so you don't have to reorganize your system and / or your room to switch between mono and stereo. (I have my stereo & mono on different arms, and just select the input to select between them.) It plays every album you throw at it, with the vertical compliance. I often just use it to play stereo albums....
Now, if the cart has no vertical compliance then you might get into a pickle, because restricting to mono records might not work: as some (older) monos were made with mono lathes, and others (newer) with stereo lathes! The ones cut on stereo lathes may need the vertical compliance! Briefly, you will go nuts to find out which lathe was cut for which of your recording...
If you have 5 mono records, no problem researching all 5 out. But if you have about a thousand like me, then its beyond frustrating to go through a pile of records, as you have to research each and every one, and cannot play the ones you feel like playing for the next few hours....