What is Possible?
The conspiracy theory presupposes that the West could be giving much more effective weapons, but isn't. So what could they give? Kandi doesn't give us an answer, which is quite telling. Let's explore the possibilities:
Air Power
Since the beginning of the war, UA has asked for more jets. Specifically, MiG-29s, which their pilots already know how to fly, but also American jets such as the F-15 and F-16. While it is theoretically possible to train UA pilots on these types, the training would certainly take weeks to months. On top of that, Western air power has a very long tail of maintenance and supply that is not easy for UA to replicate. An F-16 all by itself is not a terribly threatening weapon. An F-16 backed by AWACS, KC-135s, and a hangar full of spare parts and technicians is how the West projects air power and wins contests. Sending Ukrainian pilots up in Western jets without all the associated infrastructure would provide limited returns and put a lot of Western technology at risk.
On top of that, Eastern Ukraine is very hazardous for air power on both sides, given the extensive deployment of AA batteries. Both sides have lost numerous jets and pilots to MANPADS and the full range of Russian AA, from Tor to the S-400. Of course, Western air power could help reduce that threat through the use of anti-radiation missiles, but it will be nearly impossible to eliminate MANPADS risk (e.g., Igla).
Tanks
UA has asked for more tanks, but it seems unlikely that tanks will ultimately decide the war, for either side. Czech Republic and the Baltic states have donated some Soviet-made tanks from their stocks, but this is not even the most urgent ask. The US could donate numerous M1s from its sizable reserves, but again, the logistics and maintenance chain makes this a poor solution for UA. The Abrams is a notoriously fuel-hungry beast, and UA is already struggling to move enough fuel to the front to support the equipment it has. M-1A2s in Donbas would create a giant vacuum of fuel consumption that would bleed UA dry. On top of that, it requires a large team of mechanics and spare parts to keep it running. Training a crew to operate it takes far less time than training a crew to maintain and repair it. The US is not going to donate its MBTs as single-use weapons.
Artillery
The largest NATO powers have already donated close to 10% of their existing active-duty artillery stocks. Given that artillery is one of the most effective weapons for UA, and one of their biggest asks, it is hard to argue that the West is holding back. It is hard to imagine that NATO leaders will decide that it's safe to donate 20-50% of their artillery to UA. For instance, the US maintains about 1,000 M777 howitzers, and donated about 100 of them to UA.
UA also asked for rocket artillery, specifically the M270 and HIMARS. While the US has currently only committed 4 units (plus 4 more, recently), again, the bottleneck is...logistics. Rocket artillery requires a pretty significant logistics train to feed. There's no point in firing off a salvo and then waiting a week for a reload to make it to the front lines. A single pod of MLRS takes up as much truck space as hundreds of artillery shells. UA will likely get more MLRS from the US and others over time, but the slow start serves to give time to set up logistics and also let the Ukrainians prove that they can adequately protect these news toys. After all, the fire control computers and other sensitive electronics would be a nice prize for Russian intelligence.
UA has asked for hundreds of tanks, thousands of artillery pieces, and numerous jets and helicopters. When you're fighting a war for your very existence, there is no downside to asking for everything under the sun. The reality is that NATO simply doesn't have the number of usable tanks and artillery guns that UA wants, and their ask cannot really be fulfilled.
NATO
The problem is that NATO relies on air power to do the jobs that RU and UA use artillery for. Until UA is ready to operate and maintain modern NATO jets, the most effective portion of NATO firepower simply won't be available to them. Saying that NATO is holding back to play a geopolitical game is just ignoring the basic facts on the ground. When Kandi gives us examples of other states that have switched from Soviet fighters to NATO fighters in a matter of weeks, complete with maintenance and logistics trains, then we can have a serious discussion.
And let us not forget that Western powers started out only giving light weapons (man-portable) and were reluctant to give any heavy weapons (self-propelled, armored). Note now that virtually every NATO member is now sending IFVs, APCs, towed and self-propelled artillery, including the very newest, top-of-the-line models (e.g., PzH 2000). This does not comport well with the "West is holding back" thesis. There was even talk of UA receiving Leopard 1 tanks, though the rocket artillery is likely more valuable to them. There was also talk of MQ-1 drones, but that is also on pause due to the sensitive electronics onboard.
But don't take my word for it. Just ask Putin whether the West is holding back. Given all the nuclear threats made so far, Putin is treating Western arms support like an existential crisis for Russia, not some geopolitical stalemate.