Is there a good reason that you don't want to use one of the existing (and very inexpensive) modules? A lot of them have similar or identical pinouts, so you can experiment and make sure there is a hardware/driver combo that you like.
IMO, the FTDIs are still good products, if you're careful to get non-counterfeits. Various people are mad at the company, for their "driver bricks counterfeit chips" driver. Their newer chips (FT230X/FT231X) are smaller and cheaper. AND there are official, tiny, modules...
CP2102 and Prolific are common choices as well, but the "counterfeit" landscape is confusing. ch340g is a newer Chinese Chip a a relatively friendly package (SOIC), but it needs an external crystal, and I don't know if you can find a "real" vendor.
Microchip has a chip that is actually a pre-programmed PIC microcontroller, and so is potentially "fixable." (also needs a crystal. But newer PIC microcontrollers don't. Go figure.)