The first major difference that i am going to talk about it the difference between p.v.p. an p.v.e.
So what is different about the p.v.p. you must be thinking? Because it is the same game of course. But there is actually a big difference between the p.v.p. Please keep in mind that when i am talking about the java p.v.p. I am talking about the modern p.v.p. And not 1.8 and earlier, But in java the combat it heavily based on critical hits and timing your blows, but in bedrock it is more about spamming and sprinting at you opponents so you can get the most hits. An other main difference between the two versions is the best melee weapon to use. In bedrock the main weapon that you would use is the sword end or story, but in java you have the choice of using the axe or the sword. Now most people would say that the axe is better and while it is more versatile i will not say that it is better. So the axe is good for doing a lot of damage in one hit, but the sword is better for doing more hits. Now in the early game for most players the preferred weapon is the axe, later gameplay when most player have optimized items with enchantments the sword can have more enchantments and is therefor considered the better item to have. Please note that the axe can disable shields and that will be mentioned furtherer. An other difference between java and bedrock is the fact that there is armour toughness in the java version of Minecraft. What armour toughness does is it reduces additional damage that the armour would normally not (please not that only diamond armour and netherite armour are the only armour that have armour toughness) and finally the finally main difference in the combat systems are shields. So shields in bedrock have not recharge and can not be disable for a period in time and can only be broken. In java on the other hand a shield can be disabled on an axe crit for 6 second leading to much more balanced p.v.p.
Here are some photos of attacks in te different versions of minecraft
here is a photo of the attack indicator in java
now here is a photo of the attack indicator on pocket edition of bedrock minecraft (phone, ipad and tablet) :