The search argument is the clearest. Somebody looking for a particular service searches for that service, and a page dedicated to it can answer that query directly while a combined page divides its relevance across several topics. Search systems assess what a page is about, and a page about four things is meaningfully about none of them.
The conversion argument matters as much. A visitor arriving with a specific problem should land on a page addressing that problem, not on a menu of everything you do. Every additional option before the answer reduces the proportion who reach it, and a combined page makes the visitor do work you could have done for them.
The practical argument is the one businesses notice first. When somebody asks what you charge for a particular service, you want a link that answers exactly that. A general services page requires the recipient to scroll and interpret, and that small friction is paid in every sales conversation you have.
Each page needs enough substance to justify existing, which is the constraint that determines how far to take this. A service page should describe what the service is, who it is for, what the process looks like, what it costs or what determines the cost, and what happens next. If you cannot fill that for a service, it may be a component of another service rather than one in its own right.
Do not split beyond what is genuinely distinct. Four services with four pages is correct. The same service described four ways for four industries is usually thin duplication, and search systems recognise near identical pages and select one of them arbitrarily. If the pages would share most of their content, one page with sections is better.
Link them together deliberately. Each service page should reference the others where relevant, and the general services page becomes a hub pointing to each rather than a container holding all of them. That structure is easier to navigate and it signals the relationship between the pages.
Keep the navigation shorter than the page count, which sounds contradictory and is how good sites work. A services menu item leading to a hub, with the individual pages reachable from there and from within relevant content, avoids a menu that requires reading.
Then check after a few months which pages actually produce enquiries, because the distribution is usually more uneven than expected. One service page frequently produces most of the business while another produces none, and that is information about what you should be selling rather than only about what the page says.
Write the pages in order of what you most want to sell rather than alphabetically or by what is easiest to describe. The first one will be the best because it receives the most attention, and putting that attention on your most profitable service rather than your simplest one is a decision worth making deliberately.
Give each page its own title and description rather than variations of a single template, since those are what appear in search results and determine whether anybody clicks. Four pages sharing a near identical title compete with each other for the same appearance, and the one that gets shown is chosen arbitrarily rather than by you.
Link each service page from the relevant articles you publish, because that is where somebody researching the problem is already reading and it is a considerably warmer route than the main menu.