In a Japanese translation of exerpts of the Lotus Sutra, there is kanji which is used that is to varying degrees still used today. Some of them are relatively common in normal speech or writing, whereas others seem to me to be more stilted or only used in formal writing (e.g. 無量 as muryō). Other times, there was kanji used that is still commonly seen in writing, but when one says it, there is a different name for it (e.g. 力 is used in the text and is written in katakana as "りき", but I believe that nowadays, its said, "ちから").
What is the name of this dialect (if there is one) and is it just a temporal difference that caused this contrast- similarly to how Shakespeare sounds weird to English speakers in the modern day. And lastly, is there a way to learn more about this type of Japanese?
Here is a link to a webpage that has the translation written in romaji. I couldn't find one that had just the Japanese and kanji on it, so I just have a sample photo below: