Warning: late night but still buzzing brain dump below:
Can you list a little more about your experience? You say you've been in the PC shop since leaving school, how long has this been? I ask this as it makes a difference to which certifications/areas of study make the most sense for you/are most appropriate for industry optics. Could you say which parts of the job you enjoyed, which parts you didn't, and if you have any proclivity towards something specific already? For example you mention networking, is this because you enjoy it/are interested in?
As for certificates, yes people are right about CompTIA but only in certain areas (for example, CySA is well regarded as far as I know).
As for me, I did the CompTIA trifecta, partly to rubber stamp myself and partly to give myself a structured path to knowledge/commitment to testing it outside of my day job (RAF IT tech at the time) that doesn't really exist anywhere else. With hindsight, A+ was a waste of time and I sort of knew it, but I thought doing "baby's first cert" with knowledge I mainly knew inside and out was a good idea, and in a way it was. I learned how to self study around a full time job, and worked out the exam experience in a low pressure environment due to not stressing about the actual knowledge. I suppose in a way it was fundamental, but I also had done Cisco IT Essentials (identical to A+ exam objectives) during tech training so it was definitely just an update. I'd say anyone with any real IT experience shouldn't do the exam, but going over the topics can't hurt as a baseline/exploratory exercise.
Network+ was more interesting, but again I had already done some Cisco stuff (Introduction to Networks, part 1 of what was a 4 part CCNA course [ccna exploration]) back in tech training, so it was a refresher. Net+ didn't spend any time teaching commands like Cisco did, just networking concepts, which I actually think is more useful for entry level bods. Things have changed however, and if I was looking at this now, I'd instead choose to do CCNA. At the time, the CCENT and CCNA certs were a little more focused/deeper around core networking concepts and services, ignoring areas outside this such as security, wireless and voip, whereas now they've brought it down a notch and spread it out to include much more content from these other areas. With that in mind, CCNA has actually become a lot more like Net+, which is good because it makes Net+ not really have any reason to exist and it's an easy choice imo. As stated, the image thing is real and Cisco's image in the UK is way beyond CompTIA's - for networking at least - so I'd forget it and do CCNA if you want to expand your networking knowledge.
Security+ was me wanting to finish the trifecta and also went alongside the Cisco Cyber Ops cert I got after going through their scholarship program for free training + exam fees. It's super generalised, almost to a fault really. I wouldn't recommend it unless you want to push for a security role that's not covered by any other specialisation, there's probably more specific stuff you want to be looking at depending on the role.
It really ultimately depends on what you want to end up doing. If you don't know the answer to this question yet, there's no problem with that and keeping it broad at first is what I'd do. If you wanted you could just become a total Microsoft monkey and get MS certs up the proverbial, nothing wrong with that. The same can be said for AWS or GCP. The A+ may help with informing this a bit more, and before wasting time deep diving it's important to work out what you want to do. I see a lot of people coming in to IT saying they want to be security, network engineer, or a dev, but with no idea just how much each role differs.
Means you have plenty of experience already in IT.
