I have created lots of edu posts for my clients in the past. Let me tell you briefly about it.
Type 1 edu links: These links are the genuine edu links. Links when some professor or edu site owner (generally there is inhouse team for each university that handles website ) link your website in content. These links are
almost impossible to buy. best approach is to have high quality of content on your site and hope that people will link them. You can sometimes pitch your website content to some university authorities. But there is no assurance that it will result in you getting links.
Type 2 edu links: For these links you have to find a way to drop your link on edu sites. Several edu websites offer forums, blogs, eportfolios etc etc on their website. Few years ago, most of such platforms were free to register for anyone. But because of getting heavily spammed, most of the edu sites have limited registration on such platforms and only genuine students and faculty can log into those platforms now.
But still there are very few platform left where you can drop your links by registering for free.
Also, you can buy student logins from the students of any university. Although this requires alot of efforts. There are few other sources to get such logins. But these are very hush hush



.
Also
Type 2 links can get deleted anytime. If anyone from website maintenance team find out any spam or irrelevant link/content they take it down immediately. Sometimes whole platform dies its natural death. Example: A platform created for a particular event of a particular year. It gets removed after the event is over. Or say the student on whose page the link is posted gets graduated from university and his page is archived.
You can find some fiverr gigs offering edu links for cheap. But I would recommend to stay away from them because of
1) Most of these sellers post on .edu.xx domains rather than .edu domains. .edu.xx are other countries educational domains. It looks spammy if you have a website targeting commercial interests in USA and have links for .edu.xx domains
2) Most of these links are made by automation. Even if made manually, their quality is very bad. Anyone can figure out that these are spammy promotional links just by looking them. Such bulk links have very less chance to stick and overall they may harm your website's ranking prospects.
I would simply suggest you to not get obsessed with edu/gov links and try to build natural link profile for your site.
Remember the oldest rule in SEO Playbook:
Content is the King