Java (Spring) - page generation on the server, pros and cons, resources, load?

Question

JavaScript

Hello, let me ask you a little holistic question, because I'm fighting for and against, I can't decide..
A project is being made. In general, the site will have to build various graphs and carry out calculations based on data from the user. That is, to make calculations, build a graph, chart in js.
I can't figure out how to make a frontend. Where to do page generation. Leave this opportunity to the server or leave this work to the client browser?
Server:
- everything will be in one Spring Boot project;
- easier to configure Security;
- the load on the server increases - is it much?
- I am mainly a back-end developer and I am not very interested in front-end;
Customer:
- the server will be a little unloaded - much? I can’t find statistics, how, for example, will the server behave if the rendering task is removed from it, for example, with 100 simultaneous sessions?
- dances with tambourines are increasing, configuring a new project, setting up dependencies, for example in Angular 2 TypeScript - it didn’t work out the first time, and I’m a little far from it. Increased development time.
....
The main essence / meaning of the question.
1. What development option would you recommend from your experience?
2. What are the other benefits of either approach?
3. Will it greatly affect the speed of page generation if the rendering will be done by the user? What if it happens on a smartphone?
4. Will the page generation speed greatly decrease if, for example, there are 100 simultaneous sessions. I understand that it all depends on the channel and server performance, but still ...
Thank you!

Answer 1

Until recently, there was a howl about indexing sites with client-side rendering. but, like, the search engines have wised up.
quick start (smoothie flavored)