Is there any way not to lose inventory after dying other than commands and chests

Without using any commands on default settings, it is impossible to not drop items on death. This is most unfortunate, but the reality of the survival gamemode. The best thing you can do is to not die, and while this may seem obvious, there are many ways to better achieve this.

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• Equip (Better) armour - Wearing armour, even leather armour, will protect you from hostile mob attacks by some degree. Wearing a full set of Netherite can deflect up to 80% of damage from direct sources such as mobs and magma blocks.
• Protection is your friend - The protection enchantment on armour can block other forms of damage where armour cannot, such as lava damage and fall damage. A full set of netherite armour with complete Protection IV (The maximum level) can deflect up to 89.92% of damage.
• Eat well and often - Healing is dictated by a hidden mechanic called Saturation. Think of it like a secret, second hunger bar. Natural health regeneration feeds off your saturation bar before sapping your hunger bar, and if you are at full saturation you will heal large amounts of health rapidly. What is the difference between a pumpkin pie and a cooked porkchop? Saturation. Porkchops and Pies both provide 8 points of hunger, but while pumpkin pies only provide 4.8 points of saturation, cooked pork provides a whopping 12.8 points of saturation. Significantly better for healing.
• You will grow to love golden carrots - Following on from saturation, golden carrots restore 14.4 points of saturation, and 6 points of hunger, meaning they are advantageous for generous healing because you can eat multiple easier than something that fills you up more, as well as the fact that in recent versions of the game gold has become much more abundant thanks to such gold sources as nether gold ore, ruined nether portals with golden loot and the occasional gold block coupled with the ease of carrot farming.
• Take your time - This applies in two ways. If you are careful, you will receive less damage than being reckless. Additionally, you should take your time in your safe place to take only what you know you need. If you do die, you do not want to lose all you hold dear.
• Totems of undying can help- Special pillagers who practice the dark arts (The evoker) can be encountered in dark oak mansions and in the final waves of a village raid. This is somewhat a double edged sword however as to get their loot that prevents death, one must risk a great deal as they can be tough opponents.
• Remember where you live - Writing down the coordinates of your home ensures that if you died with only the bare necessities, the rest of your possessions is not lost in the near infinite landscape of whatever dimension you choose to reside.
• You are near god-like - Never forget you can manipulate the world to your will. You can build, break, bridge and burrow your way through the world. Never forget this, as being able to destroy and place blocks at will is something only players can do. Zombies can't jump, Skeletons can't shoot through walls, and creepers can't blow you up if they can't see you. Your best advantage is near infallible when used right.

If you are not familiar with the game, or played long before 1.9 you may think Minecraft has simple combat mechanics, clicking rapidly. This is false. Combat is deceptively more complex than the game lets on.

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• You have a recharge bar, you can see it below your crosshair or near your exp bar depending on your settings. When it is full, you will deal more damage.

• Your fists are a very poor weapon, but better than not being able to fight back at all. Punching has no cooldown and deals a point of damage (Half a heart).

• Swords extend your attack range and recharge rapidly, with even a wooden sword dealing much greater damage than your fist.

• Axes deal more damage than swords, but have normal range and a slower cooldown.

• Tools deal more damage than your fists in a pinch, but otherwise are ineffective.

• If you jump and attack while you fall back down, you will deal a critical hit for more damage. If you sprint while attacking, you will knock back enemies further.

• Shields can Block 100% of incoming mob damage provided you give it enough time to "wind up" (Around a second factoring in average server latency.) This includes explosions and projectiles, like creeper blasts and a skeleton's arrows.