Matthew 23:23 Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone.
Open your bible to Matthew 1:1 and lay the New Testament portion on a table edge, with the Old Testament hanging over the edge. It will fall will it not? Now do the opposite, lay the Old Testament on the table and the New Testament over the edge. It is no surprise that the Old Testament will support the New Testament and not allow it to fall.
That is a matter of physics. If you could weigh the spiritual matters, perhaps the reverse would be true. Perhaps. What did Jesus say? Judgement, mercy and faith and the things that ought to be done are in the Old Testament. Have you found them? Do you even look?
Grace is such a large part of our Christian heritage that we tend to bathe in it. Saved by grace thru faith is in the forefront of our minds and experience. It is easy to find in the New Testament and that is perhaps why the majority of our reading time is in the New Testament. I will not fault anyone for reading their New Testament.
Do the weightier matters keep you from reading the Old Testament or is it that you only enjoy light reading?
Deuteronomy 11:18 Therefore shall ye lay up these my words in your heart and in your soul, and bind them for a sign upon your hand, that they may be as frontlets between your eyes.
Hebrews 10:16 This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;
The Lord said it and the Lord did it.