There are two types of anti-malware program.
The first (such as the 'Premium' version of Malwarebytes, which you have to pay for) 'runs in the background', meaning that (like your anti-virus software) it's constantly checking everything that arrives via the internet. Anything that 'runs in the background' carries a theoretical risk of conflicting with other software that runs in the same way - but I've never heard of Malwarebytes PRO being responsible for any such conflicts.
The other type of anti-malware program simply 'runs on demand'. (i.e. it carries out a scan whenever you tell it to do so but otherwise it does nothing). The
free version of Malwarebytes works in that way.
Most people (including me) seem happy enough to just use the 'run on demand' software, using the 'quick scan' option perhaps once per week.
The free version of Malwarebytes Anti-Malware can be downloaded from here:
https://www.malwarebytes.org/free/
When installing it, take care to de-select the option to install a free trial of the Premium version. Use the 'quick scan' option to run it but don't be surprised if such a scan still takes over half an hour. If the program reports that it's found malware, click the button to view the results, ensure that there's a tick alongside everything found and click the button to remove it.