Hi Paula,
My wife is Colombian as well, a paisa (we married in April 2022). I considered a lawyer, one on the Colombian side and one on the US side, but finally decided to fill out the I-130 application myself online. It is really easy; the harder part is collecting the paperwork and translations.
1. Evidence - Like you, we don't have anything joint in our names. I included a document with a relationship timeline including photos with family and friends, samples of text conversations from early in our relationship, and copies of our boarding passes from traveling together. I also included screenshots of social media posts, because those have date/times on them which help validate the timeline. I also had both her mother and my mother write a letter acknowledging our relationship, our wedding, etc. One of the challenges with submitting online is that you are limited in the size of the files that you upload, so you can't include 100's of photos. I also included a cover page to the case agent that gave an overview and an outline of the other documents of evidence. A Table of Contents, like in a book. These immigration case workers are overloaded, so I know they are making judgements quickly.
2. Once you know which form to fill out, I don't think a lawyer will be any better at putting it together than you can do yourself. The advantage of doing it yourself, and doing it online, is that you will be able to submit it and get your priority date sooner. I saved about 30 days doing it myself compared to using an online service or lawyer. The bigger challenge was getting all my wife's documents in Medellin (birth, marriage, etc) and getting them officially translated (make sure to translate front and back sides), only because that required her to physically go to a notary each time.
3. As others stated, the trick of speeding up processing doesn't seem to work anymore So you'll file the I-130 online, be automatically assigned a service center, and then the patience test starts...