Anyway, to respond to the OP: I hear ya. The classic strength of the wizard was versatility, as others have said. But it was also exclusivity: no other class had spells like Fireball, Lightning Bolt, Teleport, and Stone Shape. 106 cleric 216 wizard
That's no longer the case. The only primary caster class that
doesn't have access to Fireball (through domain, patron, or magical secrets) is the Druid. Bard is now a primary caster (?!) and gets classic Wizard spells like Knock, Polymorph, Leomund's and Mordenkainen's, Teleport, even Power Word Kill. Druid has all the environmental control spells like Fog Cloud, Stone Shape, Wall spells, Ice Storm, and conjurations. Sorcerer of course has all the blast spells and enchantments. Clerics... oh geez, clerics.[/quote
Sure you can pick and choose fireball out of there. But while it's true that there are other "full" caster classes, none come even close to the wizard in number and versatility of spells. The cleric has 106 spells on their spell list, a respectable number, and the second most out of any class. However, the Wizards spell list has a whopping 216 spells on their spell list, over double that of a cleric. Sure, the cleric can get access to some of the staples like fireball if they pick the right subclass, but there are a ton of spells that they don't get. A light cleric's spells will be worthless against a fire elemental, but a wizard could have lightning bolt or cone of cold ready. None of the Mordenkinen spells are on the Cleric's list, as well as none of the illusion spells. They removed Miracle, so Wish is unique to the Sorcerer and the Wizard. Clone, Dominate Monster, Prismatic Spray, Teleport, Force Cage, Flesh to Stone, wall of force, telekinesis... I could go on. The Wizard is just as viable as it ever has been.
What does that leave the wizard? Ritual magic is AMAZING, but most primary classes get it and literally everyone (even the 8 Int half orc barbarian) can get it with a feat. The schools give interesting flavor (I really like the conjurer) but except for the diviner the effects aren't all that mechanically powerful.
That's one feat that could be used on a heck of a lot of different things, and I find that gaining any sort of class feature is just a feat away. Wizard has less hit points than the rest? Why not take Tough?
Reading your lament, I suggest you switch to a Light domain cleric. Blast away with Burning Hands, Scorching Ray, and Fireball. Use channel divinity to fry every enemy creature within 30'--and do this at least once per short rest. Turn or destroy undead. Use your reaction to give attackers disadvantage. Wear medium armor and a shield. Take the Magic Initiate feat to get access to Eldritch Blast (you do have a high Cha, right?). Now you can blast, you can battlefield control, you're well-protected. You may not be a god, but you're friends with one.
Remember that combat is only 1/3 of the game. There's no way a cleric is as useful when it comes to exploration and dungeon delving.