When I had a working holiday visa and lived in Canada I had a friend from the UK who was applying for a permanent residence, this was before I got married and me and my (now) husband had only just briefly looked over the application process. Since she was in the middle of it I obviously asked her for advice and she SCARED ME SO BAD! lol. I don't think she ment to but she was talking about how extremely complicated the paperwork is and how it's absolutly impossible to get through it on your own and without an immigration lawyer, It's also worth mentioning that from what I understood she had a straight forward application.
But now when the time actually came to apply for my own PR can you imagine how much anxiety I had because of this? lol I was terrified! But I'm proud to say me and my husband did it completely on our own. I can understand people who may have a complicated application and possible red flags hire a lawyer. But if you have such a straight forward application there is no need for a lawyer, save your relatives money or maybe spend them on a nice vaccation instead, lol
Good Luck!