Honestly, it depends on what you are doing, but there are definitely ways to keep things organized when receiving a lot of emails.
Just to give an example of my own job (I receive 50-100 or so emails per day), I use Outlook and make use of rules. Within my inbox, I have specific folders for each of the teams I work with, I have a folder for company-wide emails, I have folders for specific tasks I perform, and I have folders for projects that I work on.
The way that I set up rules is basically just to keep a list of important keywords and keep an up-to-date contact list. For the different teams, we have a robust active directory where everyone is discoverable, so I just grab names from a given department and add them to distribution lists labeled essentially “Team A”, “Team B”, etc. When I get emails from people who belong to those teams, I have rules that look for anyone belonging to those groups and automatically drop them in those folders.
For company-wide emails, those typically originate from a limited number of senders who handle communications, so I do the same thing and just drop them into a news/announcements folder.
For vendors, they’ll send emails from specific domains, so I add a rule to filter emails from those domains, regardless from who, and drop them into labeled subfolders within a larger “Vendors” folder.
For tasks that I work with, there are always keywords in the subject field that specify the nature of the request. If it’s a ticket, for example, I’ll create a rule looking for the keyword “Ticket” and drop them in the Tickets folder. If it’s for user enrollment, I’ll look for “Enrollment” and drop it in the New Users folder (and these always come from just a couple email addresses so I put those in the requirements, too).
For projects, we do a bit of intersecting. I’ve got people from different teams and different vendors who are working on a specific thing that I want to keep together. So here I do my best to identify the specific people involved with this project, and also identify common keywords I expect to see in the subjects of emails. So for example, if this is a project to install widgets in the conference room for improved synergy, I’d set a rule looking for the specific names on the project and keywords like “widgets”, “conference room”, “synergy” in the subject line, prioritize these over the other rules, and it catches about 90% of the emails I want it to, leaving me just a few that land in other places that may need to be manually sorted due to ambiguously named subjects (For the love of god, if you are emailing about a project, put some indicator about the project instead of just putting “Hey” or “Status Update” in the subject line).