First, work on one thing at a time. Do not cheat on this. If you start Boringest Task Ever and then decide, "eh I'll browse Stack Exchange" or "I'll just code a bit which is way more fun" then you will never successfully stop doing the "ignore crappy tasks" problem.
If you have to, scope out your Boringest Task Ever into smaller pieces. Or close down multiple monitors.
Second, figure out if the not fun stuff actually is important. A lot of tasks are... not really that important. Or there is no meaningful consequence if it doesn't get done. A lot of reports and updates can fall into this category. Given you are asking this question, some of your less than fun tasks must fall into this category.
Everything has different levels of importance. If you always work on things that are generally known to be actually a priority and actually important, you don't have to deal with a lot of the Boringest things. Because a conversation with your boss can go, "I currently have High Priorities [and fun] X, Y, Z, and also Boringest Tasks Ever, which do you want me to focus on?" and your boss can try to support you doing important things.
Basically, try to work on things which are both important and fun.
Third, figure out what time of day you are best at doing the different tasks. For myself, immediately after lunch is when I'm the slowest. My body naturally is lower energy then. I do email and presentations and stuff like that then - it's low energy tasks (which I don't like doing when I'm "high energy"). But from ~3-6pm? I'll take on the world. My brain engages and I just plow through stuff.
Figure out what times are good for you or bad for different types of activities. Allocate tasks accordingly.
Fourth, delegate. You might be lucky and someone likes doing the Boringest Task Ever. You never know...
Last, timebox things. Give yourself X minutes to work on Boringest Task Ever. This is particularly effective if you actually succeed at focusing on one thing. They wouldn't call it "work" if you wanted to do everything you had to do...
Or just get an intern. ;)