There are a lot of great resources out there. The best modern beginner friendly resource I am aware of is Scratchapixel[0]. Back when I was first learning 3D I used to follow tutorials on places like NeHe Productions[1], which is probably a bit dated these days.
For more comprehensive information on all kinds of techniques, with examples from big games for each technique, the absolutely best resource is the book Real-Time Rendering[2].
If you're interested in ray-tracing rather than rasterization (i.e. more film than video games) a lot of people recommend "Ray Tracing in One Weekend"[3]. If you want to learn state of the art ray-tracing in depth, with all the math and and theory, the best resource is "Physically Based Rendering: From Theory to Implementation"[4], which is freely available online.
[0] https://www.scratchapixel.com/
[2] https://www.realtimerendering.com/
The most useful resources I've found for graphics are scratchapixel, UC Davis' graphics lectures, songho's articles, and Essential Math for Games and Interactive Applications. I highly recommend you read this last resource front to back. Seriously, its the best freaking math reference for graphics out there.
But knowing theory is not sufficient. You also need to get your hands dirty by writing code: learn how to build a software rasterizer (check out Tiny renderer) and a ray tracer (Ray Tracing in One Weekend series). Preferably in a language like C++. Then move onto APIs. I recommend you learn OpenGL, but if you're okay with being confused as all hell try Vulkan. Or WebGPU if you're a hipster (/s).
Finally, try to build some stuff. A simple engine. A non-trivial technique. A game. Whatever.
Unfortunately, you're unlikely to get hired working as a rendering engineer without having serious connections, or by having adjacent experience in the industry. Doubly so now that everyone is convinced junior engineers are unnecessary.
(Disclosure: I contributed a chapter.)
TinyRenderer: https://haqr.eu/tinyrenderer/
ScratchAPixel: https://www.scratchapixel.com/index.html
3D Computer Graphics Programming by Pikuma (paid): https://pikuma.com/courses/learn-3d-computer-graphics-progra...
Ray-tracing:
Ray Tracing in One Weekend: https://raytracing.github.io/
Ray Tracing Gems: https://www.realtimerendering.com/raytracinggems/
Physically Based Rendering, 4th Edition: https://pbr-book.org/
Both:
Computer Graphics from Scratch: https://gabrielgambetta.com/computer-graphics-from-scratch/
I'll also link a comment[1] I made a while back about learning 3D graphics. There's no better teacher than manually implementing the rasterisation and ray-tracing pipelines.