Buy the HubSpot CMS if you can afford it comfortably. $300 / month or even $270 a month is a lot more than the $49 a year you could pay to to host a self-hosted WordPress site, but HubSpot and WordPress are the kinds of products where you tend to get what you pay for.
HubSpot CMS is built for the kind of people who buy Apple laptops : they know they're paying more, but they also know that the company takes it reputation and its products VERY seriously and will stand behind them.
At the time of this writing (December 2020) WordPress is for the kind of people who aren't afraid to search through online forums for help and know that this enterprise is cheaper, but is almost certain to have pitfalls within the first 12 months. Those pitfalls are not insurmountable, and an experienced WordPress developer or even WordPress consultant can fix them, but expect things to break.
There is a lot more to write about this. Respond below if you have specific questions. Those are the most fun to write about.