>>24781It's kinda hard, but I guess there are ways you could DIY. You either need to learn yourself or have someone (or some group, company, whatever) TRUSTABLE do a (paid) pentest on your devices and network for you (and it's expensive).
There are tools that could help you, tools that defensive/SOC and offensive security people use, like vulnerability and network scanners (Nessus, ), centralized monitoring tools, antivirus and EDRs (Endpoint Detection and Response software), binary/source code scanners for prevention and detection, traffic monitoring, packet inspection tools…
None of these tools are 100% reliable, they give false positives AND negatives.